The Chicago Pneumatic CP4160 P is used for concrete demolition and has become one of the stars of the CP range. Also known as the Hell Dog or Boyer Buster, the rivet busters have a low-frequency blow with hitting power equivalent to a paving breaker twice its weight. The new CPS includes a stepped piston and steps cylinder to prevent accidental ejection of the piston. Uses 11X Jumbo shank rivet buster bits.