Mini Butterball 1 Inch M Series Offset M20/M21/M30, Fenix TK11, TK12, TA21, JETBeam M1X/M2S/JET-III M/RRT-1/RRT-2 Flashlight Offset Mount for Optical Tactical Flashlight(Black) Fits all standard Picatinny or universal rail systems. Comes complete with mounting hardware for easy installation. Fits all 1-inch flashlights. Constructed of aluminum with a black annodized finish for long lasting performance. Specifically created for the M-Series flashlights.