Trijicon ACOG Weaver Adapter Fits: 3.5x35, 4x32, 5.5x50 ACOG, 1x42 Reflex (with ACOG bases) and 1-6x24 VCOG Length: 3.50 inch Color: black ACOG Weaver Adapter with Colt style thumbscrews With Colt style thumbscrews