The piston alternatives was indeed updated for perfect fit and dampening inside unique big bore surprise systems. The 2-hole pistons (1.6 and 1.8mm) are an integral part of 2.0mm and 2.5mm level options. Also, two sets of blank pistons both detailed alternatives are included for particular customized modification. All pistons are constructed of Delrin and therefore are additionally molded utilizing ultra-high accuracy moulds.