Precision CNC Billet 8620 Heat Treated Steel (not cast or MIM) Oversize Control Surfaces for Easy Engagement Lightweight but Robust Design (0.42oz-Same as Milspec Bolt Catch with smaller control surfaces) Raised "T-Shaped" Heel provides positive and distintive control surface for bolt lock back Compatible with Norgon Ambi-Catch without interference Elegant Tapered Control Surface and Skeletonized Design Bold Horizontal and Diagonal Serrations Provides Positive Purchase Versatile, Modular Design for Futuer Add-On Products Black Oxide Finish Mfg: Battle Arms Development Inc.