Cummins ISX12 G 6 Cylinder 11.9 L Compressed Natural Gas (CNG) 400 hp Engine, 2015 US EPA Label, Air Conditioner, Cruise Control, Power Windows, Engine Brake, Allison 4000HS Automatic Transmission, 12000 lb Front Axle, 38000 lb Rears, 3.90:1 Axle Ratio, 50000 lb GVWR, Air Ride Cab, Aluminum Wheels, 295/75R22.5 Front Tires, 295/75R22.5 Rear Tires, Airglide Air Ride Suspension, 194 in Wheelbase, Air Sliding 5th Wheel