Fenix ALG-18 Barrel Light Mount Fits Any Flashlight with Diameter of 0.925-1.1 with a Head Smaller than 2.7 Fits Barrels with Diameter of 0.7-0.9. With no extra tools necessary attach the mount to any gun barrel that is 18-23mm in diameter for a secure fit. For use with most of Fenix flashlights that have a body diameter of 23.5-28mm. If the Fenix ALG-18 Barrel Mount is used on a barrel with high volume rounds the heat of the barrel will require you to remove the rubber cushions before using to avoid the rubber from melting. Specifications for Fenix ALG-18 Barrel Light Mount Fits Any Flashlight with Diameter of 0.925-1.1 with a Head Smaller than 2.7 Fits Barrels with Diameter of 0.7-0.9 Anodized Finish Black: Manufacturer: Fenix Color: Black Finish: Anodized Black Additional Features: Mount Case Finish: Anodized Handle Color: Black Blade Finish: Anodized Handle Finish: Anodized Features of Fenix ALG-18 Barrel Light Mount Fits Any Flashlight with Diameter of 0.925-1.1 with a Head Smaller than 2.7 Fits Barrels with Diameter of 0.7-0.9 Anodized Finish Black: Tool-free Assembly and Disassembly Package Contents: Fenix ALG-18 Barrel Light Mount Fits Any Flashlight with Diameter of 0.925-1.1 with a Head Smaller than 2.7 Fits Barrels with Diameter of 0.7-0.9 Anodized Finish Black