The piston choices were updated for ideal fit and dampening inside new big bore surprise systems. The 2-hole pistons (1.6 and 1.8mm) are included in 2.0mm and 2.5mm thickness options. Also, two sets of blank pistons both in depth alternatives are included for individual customized modification. All pistons are manufactured from Delrin and are also molded making use of ultra-high precision moulds.