The Unity Tactical FAST Absolute Riser creates a 2.26" optical centerline from the rail when paired with most absolute co-witness rail-mounted sights, such as the EOTech XPS Series.It comes standard with a two cross bolt rail clamp, but is compatible with the FAST QD Lever. It can be paired with any FAST FTC magnifier mount. FeaturesCompatible with Most Absolute Co-Witness Picatinny Mounted Red Dot Sights2.26" Height to Optical Center Line