SRS A2/M2, High top rail.This rail is higher that the original by 6mm, it’s also longer , covering the full length of the receiver.Compatible with SRS A2/M2 models only, not compatible with SRS A1 and SRS A2.Delivered with 10-24×3/8″ screw (x5)Aluminium 6000 series, black anodizing.DESERT TECH LICENSED PRODUCT