Wiseco Performance Products piston kit includes pistons, Wiseco Performance Products XC rings, 2 wrist pins and 4 circlips. Piston set is standard size with a 10:1 compression. For 3-1/2" bore. High performance piston set is forged from a high silicone alloy. 2009-UP XL 883 cylinders cannot be overboard to 1200cc. 2009-UP applications will require separate purchase of 1200cc cylinders to be used with piston kit. After installation run engine at moderate speeds for at least 500 miles, avoiding excessive running in lower gears, in order to properly break-in new pistons and rings.