Piston Ring Expander 2" To 4" CapacityReplaces Part Numbers Piston Ring Expander 2" To 4" CapacityOEM Numbers : Piston Ring Expander 2" To 4" CapacityType : Piston cylinder ToolsDescription : For installing and removing piston rings without the danger of breakage or distortion. No adjustments needed. All rings expanded whether step-cut or diagonal cut.