Hi Compression piston set, complete with rings and pins.(9.8) Inc pockets for real fast cams. This forged pistons are stronger and have a compression ratio of 9.5 You can run cams with an extreme lift up to 12 mm and a opening time off 300 degree for this there are special pockets in the top of the piston to give the valve more space. A set of 6 pistons contain new rings and piston pins. And come with 6 new linners,incl paper gaskets.