2-1/8" to 5" Heavy Duty piston ring compressor, we use these to re-size the PTFE sealing rings on hydraulic cylinders before re-assembly. Case, Ford/NH, Deere, Hitachi, Kobelco, Caterpillar etc. use PTFE (teflon) piston seals on most cylinders built for the 1980's onward. When the PTFE seal ring is installed it becomes stretched out & needs to be re-compressed (re-sized) before re-assembly in order to keep the seal ring in the groove & prevent damage when re-assembling the cylinder.
This ring compressor has a convenient ratcheting lock mechanism that is easily released by a lever. All steel construction.