JayCee Tapered Ring Compressor. This tool installs the piston in the cylinder in seconds. Just slide through the piston (rings installed) and put the tapered ring compressor onto the top of your cylinder. Also eliminates any rings from over-lapping. Available in 85.5, 87, 88, 90.5, 92, 94, 96, 96.7 and 96.9mm.