SureFire 660 Classic Universal Weapon Light 65 lumen tactical-level output with compact reflector for interior and close-range Applications Switches-momentary-on tape (7 inch Mounting system-tube clamp for barrels or gas tubes from 5 to 9 in diameter Construction-high-strength aerospace aluminum with Mil-Spec Anodizing; impact-resistant Polymer; coated tempered window Weatherproof-O-ring and gasket Sealed