The FAST Absolute Riser securely elevates block-type red dot optics with an absolute co-witness height to a 2.26″ optical center line. The FAST Absolute Riser provides an elevated M1913 Picatinny platform for direct attachment of optics, such as EOTech XPS, Leupold LCO and other absolute co-witness optics. It can be paired with any FAST FTC (Flip-to-Center) magnifier mount. It comes standard with a two cross bolt rail clamp, but is compatible with the FAST QD (Quick Detach) Lever. If you’re running a lower 1/3 co-witness height optic, you need the FAST Optic Riser. FAST is a series of optic mounting solutions that provides end users with a quicker sight picture than standard height mounts. FAST mounts create a 2.26” optical centerline from the rail, which allows for more rapid visual processing of the battlefield by ensuring an ergonomically correct heads-up posture. Further, they provide faster and easier dot/reticle acquisition while wearing night vision goggles, protective masks, plate carriers and other gear. COMPATIBILITY: All Direct-to-Rail Mounted Optics. Optimized for Absolute Co-witness Height Optics. If you’re running a lower 1/3 co-witness height optic, you need the FAST Optic Riser. MOUNT TYPE: 2 Cross Bolt Rail Clamp FAST QD Lever Compatible (Sold Separately) Specifications for Unity Tactical Fast Absolute Riser: Manufacturer: Unity Tactical Finish: Anodized Length: 3.6 in Height: 2.26 in Weight: 3.5 oz Fabric/Material: 7075 T-6 aluminum Attachment Type: Picatinny Mount Type: Picatinny Package Contents: Unity Tactical Fast Absolute Riser