TRIJICON HD XR NS FOR GLK 9/40 YELL: Building on the features of the current HD(TM) Night Sights, the Trijicon HD XR(TM) 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.