The Trijicon HD XR Night Sights were designed specifically with the challenges of law enforcement agencies in mind. Using Trijicon's current HD sights as an inspiration, the HD XR nights sights are next level techonology! Advanced level target identification and engagement for increased distances. The thinner front post allows shooters to have a larger field of view which further enhances the ability to identify targets, expedite engagements, and see locations for hits on target at longer distances. Pistol shooters that need the advantage of a more precise engagement in any light can count on the Trijicon HD XR Night Sights. Green tritium lamps are warranted for 12 years from the date of manufacture. Note: Professional installation is recommended.