The Fenix ALG-15 rail mount is a tactical accessory that helps to perform tactical applications; which can tool-free mounting perfectly suits the Picatinny rail (MIL-STD-1913). The compatible flashlight body diameter ranges from 22.5 - 26mm* with a light head diameter of less than 40 mm. Sturdy attachment, no fear of strong recoil. The whole body is made of aluminum alloy, and the surface is hard-anodized, which is strong and lightweight, as a powerful aid for military and law enforcement. *If the diameter of the light body is more than 25.4mm, the non-slip rubber pad in the clamp needs to be removed before installation.