BSA Piston B33/M33 1954-60 +020 with piston rings, circlips and gudgeon pin Made in Italy +020=85.5 mm Compression Ratio: 7.25:1 65-1613 Conrodincl. gudgeon pin, circlips, piston rings Piston Clearance 0.12mm or 45thouPlease look at ALL pictures - measurements