MagPul offers recoil pads in three thicknesses to help dial-in the perfect length of pull. Increase or decrease length of pull and felt recoil by switching out your recoil pad with a thinner or thicker one. The 0.55" thick recoil pad is the standard thickness for commercial stocks. The 0.70" thick recoil pad is standard for mil-spec stocks. Fits MagPul CTR, MOE, STR, ACS-L, ACS and UBR stocks. Black rubber construction.