The XS DXT Big Dot night sight is the ultimate defensive sight set. Suppressor Height Sights for Glock models 17" 19" 22" 23" 24" 26" 27" 31" 32" 33" 34" 35" & 36. Precision machined in Fort Worth" TX" XS Sights feature a Big Dot Tritium front sight and express rear sight with a vertical tritium stripe for fast sight acquisition in all light conditions. Big Dot demands your attention - even in high stress and for those with poor eyesight" aids in rapidly achieving combat effective hits. White dot reflects ambient light for best visibility in low light. Shallow V-Notch rear provides an unobstructed view of the front sight" along with a greater field of view down range" especially when moving and shooting. Day-Light" Half-Light" or Low-Light" just dot the i and center the dot over your target within 15 yards. Outside Diameter Big Dot 0.188"; fits in common holsters. Installation might require filing to fit sight to dovetail" do not use a sight press/pusher tool.