Laboratory tests have shown two distinct peaks in recoil. The explosion of the ammunition is the first, the impact of the bolt against the receiver is the second. Kick-Off 3 is a third hydraulic damper that cushions this stress on the mechanical components and further reduces recoil by an additional 10% for a total recoil reduction of 70%. Kick-Off is the only recoil reduction system in the world that uses two hydraulic dampeners very similar to those in automobile suspensions. All the other systems on the market are based on the deformation of soft materials like rubber, polyurethane or polymer inserts. Fits on specific kick off stocks for A400 Xplor and Perennia. Recoil Pad sold separately.