TruGlo's Fiber Optic sight set uses traditional fiber optics for bright aiming points, even in low-light conditions. The system utilizes Truglo's Tri-Dot aiming system by contrasting front and rear colors. It is constructed of CNC-machined steel, concealing the fibers so they cannot be seen by your target, and has TrulGo's Fortress Finish for a permanent protective coating and maximum protection. Fits Glock 20, 21, 25, 29, 30, 31, 32, 37, 40, & 41 (excludes M.O.S. models)