Machined from 7075-T6 aircraft grade billet aluminum, Precision machined magazine well with beveled feed lip for easy mag swaps, Machined and engraved to be compatible with 45 and 60-degree short throw fire control selectors such as the BAD_ASS ST 45 Lever, Compatible with most standard AR-9 components and most aftermarket parts, Take down pin spring and detent hole is threaded for a 6-32 set screw for easy capturing (hardware included), Upper tension screw behind grip screw (threaded hole with hardware included) to adjust any “slop” out of vertical fit between upper and lower, Ambidextrous trigger finger rests with grooves (above and below mag release/mag catch), Threaded bolt catch pin (Threaded hole and hardware), Integrated large opening “winter” trigger guard, Proprietary magazine catch assembly, feed ramp, and ejector is included and installed at the factory, Manufactured to MILSPEC (where applicable) on state of the art CNC equipment for consistent quality parts and exacting tolerances, Save money by building your own AR-9 rifle from the ground up exactly the way you want it configured and shoot for less!