Chicago Pneumatic’s rivet buster features a patented Controlled Power System (CPS) that prevents blank firing when a unit’s bumpers are worn out. The CPS system incorporates a stepped piston and bridged cylinder which prevents accidental ejection of the piston if the retainer is removed during operation. CPS also reduces operating costs due to broken pistons, upper and lower sleeves. The wear indicator on the lower sleeve also signals the operator the bumper is worn out and needs to be replaced. The rivet buster models include the CP 4608 and CP 4611, which deliver 8 and 11 tool strokes, respectively. Both rivet busters require 45 cfm of air for operation. Each model is available with either the D-handle inside trigger or a pistol grip external trigger.