The NBS Slick Side Billet Upper Receiver is constructed from 6061-T6 aluminum with a hardcoat anodized black finish. This upper receiver features a slick side profile with no ejection port or dust door. An anti-rotation cutout is also a noted feature of this upper receiver. This upper receiver is manufactured in the USA. Key Features 6061-T6 billet aluminum construction Hardcoat anodized black finish Slick side profile No ejection port No dust door Anti-rotation cutout Manufactured in the USA Perfect For AR-15 builders sourcing a slick side billet upper receiver