The XS Big Dot tritium night sight is a superior defensive sight. Fits S&W Bodyguard 38 with one or two retaining pins. Precision machined in Fort Worth, TX, XS sights feature a Big Dot tritium front sight 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. Day light, half light, or low light, place the bottom of the dot in the bottom of the sight channel and center the dot over your target within 15 yd. Outside diameter Big Dot 0.188 inches, fits in common holsters. Installation might require filing to fit sight to frame, we recommend having a gunsmith do the installation and drill out retaining pin holes.