The FAST COG Series is designed for most Trijicon VCOG and ACOG series optics, creating a 2.05" optical centerline from the rail.The multiple mounting holes provide optimal eye relief with an ACOG depending on the weapon platform. The modular base accepts the FAST Offset Optic Base, which allows for mounting a variety of secondary/back-up optics at the same 2.05" height and at a 36 degree angle for rapid transitions. FeaturesCompatible with Trijicon AGOC and VCOG3 Cross Bolt Rail Clamp2.05" Height to Optical Center Line