A1 Optic A1SL Remote Optic Power Switch for DOT Sights and Scopes The remote optic power switch comes in two sizes and fits most DOT sights and lit scopes* * Fits 26mm OD thread. Also available in 28mm OD thread (see may we also suggest section below). * To determine the thread size, open the scope battery cap, and is a US 25¢ coin (quarter) WILL press inside the battery cap, choose the 28 mm model (A1SS). If a US 25¢ WILL NOT press inside the battery cap, select the 26 mm model (A1SL). Prevent dead batteries, fumbling with your scope switch and giving away your position. The remote optic power switch installs easily and the pressure pad mounts to your weapon grip to insures your scope will light during critical situations. Firearm and scope pictured are not included and are shown for depiction purposes only.