The Battle Arms AR-15 Enhanced Lower Receiver Parts Kit offers a versatile modular design, enhanced control surfaces, lightweight engineering, and better ergonomics. This kit a cost-friendly alternative, without sacrificing the quality for your AR build! All parts are 8620 heat treated cast steel with a manganese phosphate black finish. Includes:Enhanced Bolt CatchLightweight but Robust Design 0.39ozCompatible with Norgon Ambi-Catch Without InterferenceRaised "T-Shaped" Heel Provides Positive and Distinctive Control Surface for Bolt Lock BackBold Horizontal and Diagonal Serrations Provides Positive PurchaseEnhanced Single Sided Safety Selector Based on the BAD Ambidextrous Safety Selector with distinctive and diagonal serrations Enhanced Magazine Catch Construction: One Piece Engineering (Not Two-Piece)Design: Lightweight Fluted DesignCompatibility: Compatible with Mil-Spec Magazine Release Button, BAD-EMR, BAD-EMMR, etc.Length: Shorter Threaded Pin to Reduce Installed Ma...