The Hein-Werner HW93667 4-Ton Air Assist Long Chassis Service Jack is a professional hydraulic service jack engineered to improve productivity in truck, bus, construction, and farm equipment repair shops. Dual piston action provides speed to contact and power to lift. Extra-long chassis reaches under low overhangs. Features include a T-handle with a release knob and three locking positions, a cast iron lift arm, and a sealed hydraulic unit that keeps out grit, grime, and moisture. Operates manually or with air assist.