The GHOST GEN4 X-RELEASE is a drop-in extended magazine release that requires no modification to your pistol. Designed so you can operate the magazine release without changing your firing grip and so you do not have to modify your GLOCK's frame. It is designed to give you the maximum surface area possible for the comfort and speed of release. Mfg: Ghost SPECS: Fits the following GLOCK GEN4 only: 17, 19, 22, 23, 26, 27, 31, 32, 33, 34, 35, 37, 38 & 39