ZEV backup iron sights (BUIS) are designed to be used with one of the many mini red dot sights available on the market - such as Trijicons RMR. Because of this, ZEV Co-Witness Sight Sets are an excellent addition for either absolute or 1/3 co-witness applications. Zev Technologies - iron sight sets are an inexpensive addition that a Glock - owner can make to their firearm. The top 3 complaints from Glock - owners are the trigger, grip, and sights. Features: Iron sight sets have the highest resolution and greatest ease of acquisition Higher visibility will allow you to keep your sights on target The right Zev technologies, sight set will improve your shots on target dramatically over a factory glock Notch width of 0.140 and notch dept of 0.145 will allow you enough room to keep your eyes on target during transitions Zev Technologies - parts always incorporate design, feel and performance Zev Technologies - fiber optic sight sets are machined and assembled from quality billet materials and built to last