the size (printed on the piston) is the size of the cyinder liner with a piston clearance of 12-13/100mm. please note: the insturctions of IAME are 11-12/100mm piston clearance for a IAME X 30 engines. piston type green: = exactly the printed size, piston type red: = printed size + 1/100mm insdie the package is: 1 piece of piston, 1 pice of pitson ring, 2 pieces of clips |