Centurion Arms LLC, C4 5.56 Billet Lower Receiver in 7075-T6 Aircraft Grade Aluminum - Precision CNC from Billet 7075-T6 Aerospace Aluminum - MIL-A-8625F, Type III, Class 2, Hard Coat Anodized flat black finish or Cerakoted as per customers needs - Compatible with TDP/Mil Standard AR lower receiver parts - Compatible with ambidextrous controls currently on the market (ambi selector and NORGON mag release) - Dimensional accuracy inspection - All sharp edges de-burred by hand - Pictograph selector markings properly marked for 90A'Adeg safety - Multi Caliber marking for build versatility - Largest possible, flared, deep beveled magwell - Tensioning screw for proper upper/lower fit - Integrated trigger guard - All Components, material, and packaging made in the USA - Weight: 9.5 oz *** We recommend gunsmith installation for all of our parts. We cannot warranty items damaged by improper installation. **FFL REQUIRED BEFORE SHIPPING. Please contact your local FFL for transfer, and have them send a copy of their FFL to sales@centurionarms.com , and please have them reference your name/order number. No we do NOT accept fax as we live in the modern world and we also do NOT accept carrier pigeon. **