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. This mount fits all VCOG models, the 1x42 Reflex (with ACOG base), and the 3.5x, 4x and 5.5x ACOG models.