Based on an optical illumination patent, the MEPRO FT Bullseye is an extremely small, low profile, optical pistol sight. Similar to reflex sights, using the FT Bullseye provides the shooter with an aim point in the form of an illuminated dot and circle Bullseye. Shooters can enjoy intuitive and fast target acquisition. The Fiber-optic Tritium combination enables instant and accurate shooting in all lighting conditions with no batteries needed. The Fiber-optic is used in bright light or day shooting and the premium-grade Tritium provides instant illumination at night or in low-light conditions. The MEPRO FT Bullseye installation is simple and easy on existing pistol dovetails, eliminates the need for a front sight and fits most existing holsters. For GLock MOS Standard Size Only. Sight Length: 1.63″. Sight Width: 0.71″. Sight Height: 0.24″.