Description NEBO PROTEC Mounting Clamp is a universal long gun light mount. Constructed of aircraft grade anodized aluminum, this self-locking, the mounting clamp has uses an adjustable mount design to easily mount and lock to your long gun, no tools required. The PROTEC Mounting Clamp adjusts to fit 12-20 gauge shotguns and rifles, both plain and vented barrels. The clamp offers a 9 millimeter adjustment allowance.The barrel portion of the clamp adjusts from 20mm to 29mm, and the flashlight portion of the clamp adjusts from 23.5mm to 32.5mm. Adjustment is controlled by the side latch, just twist to adjust and lock.