Fitment for Trijicon RMR, RMR HD, SRO, Holosun 407c, 508t, 507Comp. Each plate is precision machined to the tightest tolerances on HAAS CNC machines and each plate goes through multiple quality checks before shipping to our customers. Precision Machined 6061Aluminum, S7 tool steel T-nut for superior attachment. MIL-SPEC Type III Hard Anodized – Black, 6-40 x 250 M3H (4) S7 T-nuts (3) 4-40 x 345 FHB (3) (RMR w/sealing plate, SRO,RMR HD ,4-40 x .280 FH (3) (407c, 507c, 508t, 507COMP)Screw packs.