The XTI express sight system from XS Sights is an offset sight system for the AR-15 style rifle designed in collaboration with Lone Star Armory. The Xpress Threat Interdiction sights are designed to be used as back-up iron sights with magnified optics. The XTI sights are offset so the primary optic will not interfere with the sights and changing between the primary and XTI sights are fast. To transition to the XTI sights simply cant your rifle outboard by approximately 15 degrees and the sights will be visible. These sights are the perfect back-up to a red dot optic in a CQB situation or patrol rifle with a magnified primary optic. The XTI sights are also an excellent addition to a Tac Optics class 3-Gun rifle for those close hoser targets. Sights are designed to be mounted forward of optic, approximately 5" apart.