This mount fits all VCOG’s the 1×42 Reflex (with ACOG base) and the 3.5x 4x and 5.5x ACOG’s. The AC12033 quick release mount utilizes a single lever system. It features the patented BLAC lever system which requires no manual adjustments to attain a proper rock solid engagement on a 1913 picatinny rail. – Height of Mount Surface to Optical Axis: 3x 4x and 5.5x ACOG = 1.535 in. – VCOG = 1.535 in. – 1×42 Reflex = 1.506 in.