This is the new 2 Ring FSR Slipper Skirt forging Piston. Drop in high compression kit includes pistons, rings, lighter wrist pins, cir clips . The compression is 13 to 1. At the forefront of performance, piston manufacturing has been a result of continuous research and development of unique materials, piston designs and technologies. Utilizing State of the Art CNC machines for manufacturing, along with purpose-designed forgings, while being able to maintain exacting specifications on each and every piston – holding tolerances to millionths of an inch.