Unity Tactical FAST MicroPrism Mount. The Unity Tactical FAST MicroPrism Mount was designed to position the Primary Arms MicroPrim optics at a 2.26? Optical centerline from the rail. It is also compatible with other optics of industry standards min-prism footprint (heights may vary depending on the optic). It comes standard with a two cross bolt rail clamp, but is compatible with the FAST QD (Quick Detach) Lever. 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. 2.26 to Optical Centerline. Primary Arms MicroPrism optics and most optics with an industry standard mini prism footprint. 2 Cross Bolt Rail Clamp. Dimensions (W x L x H). Type III Hardcoat Anodized.