6 Band Piston Ring Pliers Compressor Kit 2-7/8" (73mm) to 4-3/8" (111mm) for Engines 6 Band Piston Ring Compressor Kit 2-7/8" (73mm) to 4-3/8" (111mm) Multiple Engine use Fastest way to insert your pistons with this handy piston ring compressor tool set Piston ring bands are identified with bottom of cylinder markings for easy installation Steel Bands form around piston and rings to compress rings for insertion into bore Tool kit comes in durable carry case