Manufactured in Japan and designed as OEM replacements Cast from a high-silicon content aluminum alloy that meets or exceeds OEM specifications, then CNC machined to extremely close tolerances Available in standard sizes along with fractional increases in standard sizes Standard B, C and D sizes extend the life of expensive plated cylinders Additional oversizes available in .010 increments Pistons supplied in a kit package that includes rings, wrist pins and circlips Pro-X rings and pistons are interchangeable and compatible with OEM pistons and rings NOTE: Standard size pistons do not require reboring or rehoning your cylinder Oversize pistons will require reboring and rehoning of your cylinder