The Trijicon HD XR night sights were specifically designed with the ever evolving challenges of law enforcement agencies in mind. Building on the features of the current HD night sights, the Trijicon HD XR night sights are for the next level of advanced target identification and engagement at increased distances. A thinner front sight post allows shooters to have a larger field of view which further enhances the ability to identify targets, expedite engagements and see location of 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. Specifications: - fits: FNH models: FN509 (night sight set with yellow front outline) - color: black. Front sight: - blade width: 0.122" - blade height: 0.215" - overall height: 0.279". rear sight: - notch width: 0.169" - blade height: 0.218" - overall height: 0.309". note: professional installation recommended. Dimensions for reference only