Properly installing new pistons require the piston rings to be safely compressed without damaging essential parts. The Powerbuilt Piston Ring Compressor Set is the perfect tool to help you get those pistons installed like a pro. This top-quality set includes six band sizes and a ratcheting clamping tool, everything you need to make piston installation smooth and easy. The included six bands can be tightened to fit pistons from a versatile range of 2 7/8-inches(73mm) up to 4 3/8-inches(111mm). Good for most applications. Simply attach the correct sized band, tighten with the clamping tool until the required size is reached, and the band will hold the piston ring securely until the piston is reinstalled. Keep your kit well organized and protected for a lifetime of use in the heavy-duty carry case. Helpful detailed instructions and usage photos are included.