Hybrid piston consists of three different materials: Light aluminum body, two POM rings for better sliding in the cylinder and piston catch from stainless steel. This piston, specially made for the CYMA - CM.702 Thanks to durability it can hold strong springs and improove your shooting range. Inner diameter has been enlarged and can fit stronger 13mm upgrade springs. Piston length is 118mm, outer diameter 13,3mm. Suitable only for CYMA CM.702 !!!