MaxxForce® Engines
Power for International Trucks
The only engines with hassle-free MaxxForce® Advanced EGR technology that allows the driver to focus on the job at hand. Without worrying about meeting 2010 emissions requirements.
DuraStar
MaxxForce 7
Engine
Impressive Fuel Efficiency, Power and Quietness
215-300 hp
560-860 lb.-ft. of torque
The DuraStar® is the perfect platform for the MaxxForce® 7. The newly-designed MaxxForce® 7 features the industry's most precise high-pressure common-rail fuel injection system,plus an advanced air management system, producing outstanding fuel economy, power, performance, reliability and durability. All that is accomplished with low noise, making the MaxxForce® 7 ideal for in-city applications.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Best in class horsepower and torque
- The quietest V8 diesel engine in North America, registering only 68.9 dBA in a low idle test
- 13% more fuel-efficient than previous models
- A DC-actuated turbocharger provides impressive acceleration, grade climbing, towing capability and high-altitude performance
- For city routes, double-digit percentage fuel economy improvement is possible when the transmission and drivelines are optimized
DuraStar
MaxxForce 7
Spec
- Configuration
- V-8
- Displacement
- 6.4 L (389 cu. in.)
- Power Output
- 220-300 hp (164-224 kW)
- Peak Torque
- 560-660 lb.-ft. (762-898 Nm)
- Aspiration
- Turbocharged
- Combustion System
- Direct Injection
- Dry Engine Weight
- 1,225 lbs. (556 kg)
- B50 Life
- 350,000 Miles (603,504 km)
- Valves Per Cylinder
- 4
- Cylinder Design
- Parent Bore
- Block Reinforcement
- Single-Piece Bed Plate, Retains all 4 Bolt Bearing Caps
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® 7 Brochure PDF
DuraStar
MaxxForce DT
Engine
Legendary Durability and Performance
215-300 hp
560-860 lb.-ft. of torque
The MaxxForce® DT powers the DuraStar® to its full potential. It has a full range of automatic and manual driveline options and thousands of possible build configurations to meet the demands of any application. Its reliability, durability, serviceability and high resale value mean the MaxxForce® DT brings real success to your operation.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Electro-hydraulic Generation Two fuel system make it 9% more fuel-efficient than previous models
- Premium plateau-honed wet-sleeve design provides heavy-duty durability characteristics of big bore engines, plus easy rebuildability
- Mechanical roller followers allow 70,000 more miles before lash adjustments than the competition
- Four valves per cylinder provide better breathing, performance and lower emissions
- Named by Diesel Power magazine one of the "Top 10 Diesel Engines -Ever."
DuraStar
MaxxForce DT
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 7.6 L (466 cu. in.)
- Bore & Stroke
- 4.49 in. & 4.68 in. (11.7 cm & 11.9 cm)
- Compression Ratio
- 16.4:1
- Aspiration
- < 230 hp Aftercooler only
- Combustion System
- Direct Injection
- Engine Lubrication
- 30 Quarts(28 L)
- Total Engine Weight (Dry)
- 1,425 lbs. (646 kg)
- Dimensions
- < 230 hp L 45 in. x W 42 in. x H 43 in.
- Valves
- 4 Valves per Cylinder
- Cylinder Design
- Wet-Replacable, Induction/Hardened Cylinder Sleeves
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® DT Brochure PDF
DuraStar
MaxxForce 9
Engine
Rock Solid for the Toughest Jobs
300-330 hp
860-950 lb.-ft. of torque
With a full range of automatic and manual driveline options and thousands of potential build configurations, MaxxForce® 9 is made to serve the broadest range of non-highway applications. Navistar engineers have carried forward the proven technologies and components of a time-tested platform like premium plateau-honed cylinder design, reinforced bearing-cap ladder and rugged single-box ECM.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Premium plateau-honed wet-sleeve design provides heavy-duty durability characteristics of big bore engines
- A new regulated two-stage turbocharger and upgraded cooling system provide outstanding boost and response for every application
- The electro-hydraulic high-pressure fuel system features new high-efficiency injector nozzles and advanced electronic control strategies for fuel economy gains
- Increased 9.3-liter displacement by longer stroke, meet the requirements of mroe demanding applications
DuraStar
MaxxForce 9
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 9.3 L (570 cu. in.)
- Bore & Stroke
- 4.59 in. & 5.75 in. (11.7 cm & 14.6 cm)
- Compression Ratio
- 17.2:1
- Aspiration
- Two-Stage Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 30 Quarts(28 L)
- Total Engine Weight (Dry)
- 1,425 lbs. (646 kg)
- Dimensions
- L 45 in. x W 42 in. x H 47 in.
- Valves
- 4 Valves per Cylinder
- Cylinder Design
- Wet-Replacable, Induction/Hardened Cylinder Sleeves
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® 9 Brochure PDF
ProStar
MaxxForce 11
Engine
Tough, Reliable and Ready to Take on Anything
330-390 hp
1,250-1,450 lb.-ft. of torque
Designed specifically for International brand heavy vehicles, with a combination of technologically advanced materials and components, MaxxForce® Big Bore engines deliver outstanding fuel economy, excellent power characteristics, an exceptionally smooth, quiet ride and high strength without the added weight. Navistar's MaxxForce Big Bore engines have revolutionized how the world looks at Class 8 commercial diesels.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
ProStar
MaxxForce 11
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 10.5 L (641 cu. in.)
- Bore & Stroke
- 4.72 in. & 6.10 in. (12 cm & 15.5 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,000 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 660-830
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 11 Brochure PDF
ProStar
MaxxForce 13
Engine
Tough, Reliable and Ready to Take on Anything
410-475 hp
1,450-1,700 lb.-ft. of torque
Designed specifically for International brand heavy vehicles, with a combination of technologically advanced materials and components, MaxxForce® Big Bore engines deliver outstanding fuel economy, excellent power characteristics, an exceptionally smooth, quiet ride and high strength without the added weight. Navistar's MaxxForce Big Bore engines have revolutionized how the world looks at Class 8 commercial diesels.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
ProStar
MaxxForce 13
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 12.4 L (758 cu. in.)
- Bore & Stroke
- 4.96 in. & 6.54 in. (12.6 cm & 16.6 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,400 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 830-960
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 13 Brochure PDF
TranStar
MaxxForce 11
Engine
Tough, Reliable and Ready to Take on Anything
330-390 hp
1,250-1,450 lb.-ft. of torque
With a schedule to keep, you need the perfect combination of engine and truck-and that's where the International® TranStar® with MaxxForce® Big Bore engines deliver. Setting new standards in reliability, MaxxForce Big Bore engines utilize a high-pressure common-rail fuel system to offer higher fuel efficiency, with up to 475 HP in a lightweight package so you can haul more, more often. And with an engine validated by over 30,000 hours in the lab and over two million miles on the road, you can drive easy with the confidence your job demands.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
TranStar
MaxxForce 11
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 10.5 L (641 cu. in.)
- Bore & Stroke
- 4.72 in. & 6.10 in. (12 cm & 15.5 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,000 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 660-830
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 11 Brochure PDF
TranStar
MaxxForce 13
Engine
Tough, Reliable and Ready to Take on Anything
410-475 hp
1,450-1,700 lb.-ft. of torque
Designed specifically for International brand heavy vehicles, with a combination of technologically advanced materials and components, MaxxForce® Big Bore engines deliver outstanding fuel economy, excellent power characteristics, an exceptionally smooth, quiet ride and high strength without the added weight. Navistar's MaxxForce Big Bore engines have revolutionized how the world looks at Class 8 commercial diesels.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
TranStar
MaxxForce 13
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 12.4 L (758 cu. in.)
- Bore & Stroke
- 4.96 in. & 6.54 in. (12.6 cm & 16.6 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,400 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 830-960
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 13 Brochure PDF
WorkStar
MaxxForce DT
Engine
Legendary Durability and Performance
215-300 hp
560-860 lb.-ft. of torque
The MaxxForce® DT powers the WorkStar® to its full potential. It has a full range of automatic and manual driveline options and thousands of possible build configurations to meet the demands of any heavy-duty application. Its reliability, durability, serviceability and high resale value mean the MaxxForce® DT brings real success to your operation.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Electro-hydraulic Generation Two fuel system make it 9% more fuel-efficient than previous models
- Premium plateau-honed wet-sleeve design provides heavy-duty durability characteristics of big bore engines, plus easy rebuildability
- Mechanical roller followers allow 70,000 more miles before lash adjustments than the competition
- Four valves per cylinder provide better breathing, performance and lower emissions
- Named by Diesel Power magazine one of the "Top 10 Diesel Engines -Ever."
WorkStar
MaxxForce DT
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 7.6 L (466 cu. in.)
- Bore & Stroke
- 4.49 in. & 4.68 in. (11.7 cm & 11.9 cm)
- Compression Ratio
- 16.4:1
- Aspiration
- < 230 hp Aftercooler only
- Combustion System
- Direct Injection
- Engine Lubrication
- 30 Quarts(28 L)
- Total Engine Weight (Dry)
- 1,425 lbs. (646 kg)
- Dimensions
- < 230 hp L 45 in. x W 42 in. x H 43 in.
- Valves
- 4 Valves per Cylinder
- Cylinder Design
- Wet-Replacable, Induction/Hardened Cylinder Sleeves
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® DT Brochure PDF
WorkStar
MaxxForce 9
Engine
Rock Solid for the Toughest Jobs
300-330 hp
860-950 lb.-ft. of torque
MaxxForce® 9 engines are purpose-built to the needs of WorkStar® drivers. With a full range of automatic and manual driveline options and thousands of potential build configurations, MaxxForce 9 is made to serve the broadest range of on-highway applications. Navistar engineers have carried forward the proven technologies and components of a time-tested platform like premium plateau-honed cylinder design, reinforced bearing-cap ladder and rugged single-box ECM.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Premium plateau-honed wet-sleeve design provides heavy-duty durability characteristics of big bore engines
- A new regulated two-stage turbocharger and upgraded cooling system provide outstanding boost and response for every application
- The electro-hydraulic high-pressure fuel system features new high-efficiency injector nozzles and advanced electronic control strategies for fuel economy gains
- Increased 9.3-liter displacement by longer stroke, meet the requirements of mroe demanding applications
WorkStar
MaxxForce 9
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 9.3 L (570 cu. in.)
- Bore & Stroke
- 4.59 in. & 5.75 in. (11.7 cm & 14.6 cm)
- Compression Ratio
- 17.2:1
- Aspiration
- Two-Stage Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 30 Quarts(28 L)
- Total Engine Weight (Dry)
- 1,425 lbs. (646 kg)
- Dimensions
- L 45 in. x W 42 in. x H 47 in.
- Valves
- 4 Valves per Cylinder
- Cylinder Design
- Wet-Replacable, Induction/Hardened Cylinder Sleeves
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® 9 Brochure PDF
WorkStar
MaxxForce 10
Engine
Strength and Power to Get the Job Done
310-350 hp
1,050-1,150 lb.-ft. of torque
MaxxForce® 10 engines are purpose-built to the needs of WorkStar® drivers. With a full range of automatic and manual driveline options and thousands of potential build configurations, MaxxForce 10 is made to serve the broadest range of on-highway applications. Navistar engineers have carried forward the proven technologies and components of a time-tested platform like premium plateau-honed cylinder design, reinforced bearing-cap ladder and rugged single-box ECM.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- Premium plateau-honed wet-sleeve design provides heavy-duty durability characteristics of big bore engines
- A new regulated two-stage turbocharger and upgraded cooling system provide outstanding boost and response for every application
- The electro-hydraulic high-pressure fuel system features new high-efficiency injector nozzles and advanced electronic control strategies for fuel economy gains
WorkStar
MaxxForce 10
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 9.3 L (570 cu. in.)
- Bore & Stroke
- 4.59 in. & 5.75 in. (11.7 cm & 14.6 cm)
- Compression Ratio
- 17.2:1
- Aspiration
- Two-Stage Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 30 Quarts(28 L)
- Total Engine Weight (Dry)
- 1,425 lbs. (646 kg)
- Dimensions
- L 45 in. x W 42 in. x H 47 in.
- Valves
- 4 Valves per Cylinder
- Cylinder Design
- Wet-Replacable, Induction/Hardened Cylinder Sleeves
- Fuel System
- Electro-Hydraulic Unit Injector G2
Download MaxxForce® 10 Brochure PDF
WorkStar
MaxxForce 11
Engine
Tough, Reliable and Ready to Take on Anything
330-390 hp
1,250-1,450 lb.-ft. of torque
To succeed in this competitive business, your truck needs an engine behind it that's always performing and working for you. MaxxForce® Big Bore engines keep you going strong. With a 1.2 million-mile B-50 life, the longest design life in the industry, means it's built to last 200,000 miles longer than the competition - No matter the pounding it takes:
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
WorkStar
MaxxForce 11
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 10.5 L (641 cu. in.)
- Bore & Stroke
- 4.72 in. & 6.10 in. (12 cm & 15.5 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,000 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 660-830
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 11 Brochure PDF
WorkStar
MaxxForce 13
Engine
Tough, Reliable and Ready to Take on Anything
410-475 hp
1,450-1,700 lb.-ft. of torque
Designed specifically for International brand heavy vehicles, with a combination of technologically advanced materials and components, MaxxForce® Big Bore engines deliver outstanding fuel economy, excellent power characteristics, an exceptionally smooth, quiet ride and high strength without the added weight. Navistar's MaxxForce Big Bore engines have revolutionized how the world looks at Class 8 commercial diesels.
- EPA compliant with MaxxForce Advanced EGR, the only no-hassle emissions solution for 2010 standards
- A Compacted Graphite Iron cylinder block is 40% stiffer with 75% higher tensile strength, and 200% greater fatigue resistance than iron used in other Class 8 diesel engines
- Low vibration levels prolong the life of the engine by protecting it from ordinary wear and tear
- Fuel system combined with twin series turbo chargers, delivers peak torque at a lower RPM, which allows for earlier upshifts when accelerating and fewer downshifts when climbing hills
- Internal testing has shown a 2.4% fuel efficiency advantage over the leading I5L engine
- Over 500lbs lighter than the nearest I5L engine with similar power output
- Peak torque is achieved at 1000 RPM (just over idle) and sustains at higher RPMs for a more responsive off-the-line driving experience
WorkStar
MaxxForce 13
Spec
- Engine Type
- Diesel, 4-Cycle
- Configuration
- Inline 6-Cylinder
- Displacement
- 12.4 L (758 cu. in.)
- Bore & Stroke
- 4.96 in. & 6.54 in. (12.6 cm & 16.6 cm)
- Compression Ratio
- 16.5:1
- Aspiration
- Dual Staged Turbochargers, Intercooler & Aftercooler
- Combustion System
- Direct Injection
- Engine Lubrication
- 42 Quarts(40 L)
- Total Engine Weight (Dry)
- 2,400 lbs. (1,089 kg)
- Dimensions
- L 59 in. x W 37 in. x H 49 in.
- Valves
- 4 Valves per Cylinder, Overhead Cam Actuated
- 800 RPM Torque Range (lbs/ft)
- 830-960
- Block
- CGI
- Emissions Technology
- EGR-DPF
- Fuel System
- Bosch High Pressure, Common Rail, Non VG
Download MaxxForce® 13 Brochure PDF
