The CP717K is a Super Duty Air Hammer Kit which includes the CP717, a 4 piece .498 chisel set and a spring style retainer all packed in a heavy duty carry case.The CP717 is the most powerful air hammer for automotive, truck and off road equipment. Heavy Duty customers will love this kit. Positive action trigger for precise control. Ideal for front end work, king pin bushing removal and installation of bull dozer walking beams, removal of truck springs and heavy duty spring bushings. .Specifications: chisel shank opening: .498", bore diameter - 3/4", piston stroke length - 2 11/16", cfm - 7, hose size - 3/8", blows per minute: 1,800.