TRIJICON HD XR NS for GLK 9/40 YELL: 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 greater distances. A thinner front sight post allows shooters to have a larger field of view, which further enhances the ability to identify targets, speed up engagements, and see the location of hits on the target at longer ranges.