The Elzetta ZFH1500 Flashlight Mount provides solid attachment of a tactical flashlight to the A1 or A2 front sight base of AR15, M16, and M4 rifles regardless of barrel type, length, or diameter. The Mount works with standard hand guards as well as Magpul MOE hand guards. No rail system is required for installation. The ZFH1500 accommodates cylindrical flashlights from 0.7 to 1.1 inches in diameter (18 to 27 mm). This includes all Elzetta Modular Flashlights. Upgrade your adapter to include a thumbscrew. The included Thumb Screw Kit allows rapid installation and removal of flashlights without tools. A coin or other flat object may be used to tighten the Thumb Screw. Made in USA.