XS R3D Tritium Night Sights feature a traditional 3-dot tritium, notch and post sight picture. The rear is blacked out to increase contrast against the front sight. The front sight is orange and equipped with an Ember Glow Dot Technology. Ember absorbs ambient light and glows in low light. The front tritium lamp charges the Ember dot making the front sight glow brighter than the rear, keeping focus down range. R3D sights are the brightest options for fast and accurate shooting in bright and low light. Tritium Powered Front & Rear Sight -Glows in low light to aid in sight alignment High-Contrast Color Front Sight - Available in bright orange or green Ember Glow Dot - Photoluminescent dot absorb ambient light and glows in low light Rear Sight Overhang - Reduces rear sight glare in bright light for greater sight definition Anti-Reflective Rear Tritium Lens - Reduces glare in bright light and increases contrast against the front sight Rear Sight Ledge - Aids in one-handed slide manipulations CNC Steel - Extremely durable for duty use 10 Year Warranty - No Questions Asked Night Sight Warranty Easy Installation - Easily install by hand or sight pusher tool Fits standard holster options Compatibility Sig P320, P365, P225, P226, P228, P229, SP2009, SP2340 Springfield XD, XD-M (not adjustable rear), XD-S, XD-S MOD.2, XD-E, HellCat FN 509 Mossberg MC1 Does not fit XDm 5.25" barrel models, the OSP Hellcat, or the P320 X series that have the rear sight attached to the optics plate.