This receiver set is meant for those looking to build a custom large frame rifle. Lightweight Ambidextrous and austheticly pleasing the NEMO XO Large Frame is a great foundation for your custom build! - 7075-T6 Billet Aluminum construction - Lightweight design - Full ambidextrous control - Tensioning screw for an assured tight fit - Includes Ambi bolt catch/release - Will work with most aftermarket Low .308 rails - Engraved T Markings - Flared magazine well