The Buffer Technologies Recoil Buffer for the Glock pistol eliminates the metal slide from impacting the polymer frame. This repeated impact batters the frame where the two parts come into contact. Stopping this battering is accomplished by inserting the buffer between the recoil spring and the slide. Each time the action is worked or the weapon is fired the buffer comes into contact with the frame, not the metal slide. Installation of the Glock Buffer will result in reduced felt recoil, enhanced muzzle control and a longer service life. The Glock Recoil Buffer will fit models 17, 17L, 18, 19, 20, 21, 22, 23, 24, 24C, 31, 32, and 37. It will NOT fit Gen 4 Glocks.