Piston Ring Compressor Set Install pistons from 2-7/8 to 4-3/8” (73 to 111mm). . Pliers can be used parallel or perpendicular to the cylinder block. . Fine-tooth ratcheting lock allows you to compress bands in small increments. . Set works by placing a band around the piston, covering the rings and hooking pliers into the band and squeezing. . With the band tightly around the piston, insert piston into cylinder and tap lightly with hammer handle to install. . Set includes pliers and 6 bands, 1119 through 1124. 850