Ultradyne USA Apollo S, Compensator, 7.62MM, Black, 5/8X24 UD10270 The APOLLO S from Ultradyne provides competition level recoil reduction and muzzle control. By using a scientific approach and studying thousands of recoil events" Ultradyne engineers have struck a balance between extreme recoil reduction" virtual elimination of muzzle rise" and less aggressive venting of gas. The Apollo S is perfect for shooters who want drastic recoil reduction with less perceived blast.