ACOG Picatinny Rail Adaptor with Colt Thumb Hole ScrewsManufacture ID: TA51Mounts optic to Picatinny rail with two thumbscrews.Specifications:- Fits: 3.5x35, 4x32, 5.5x50 ACOG, 1x42 Reflex (with ACOG bases) and 1-6x24 VCOG- Length: 3.50"- Weight: 4 oz.Height of Mount to Optical Axis:- 3.5x35, 4x32 and 5.5x50 ACOG: 1.535"- 1x42 Reflex (with ACOG Bases): 1.506"- 1-6x24 VCOG: 1.535