COATS CARBINE COMPANY offers this anodized billet 7075-T6 Aircraft grade aluminum 80% Lower with broached magazine well. NEW AR-15 FEATURES: Threaded Bolt Catch Pin -- no more pin to drive in easing in assembly. Larger Flared Magazine Well eases loading operation in high stress situations. Slack Depleting Screw threads into lower portion placing pressure against rear upper lug pressing it against rear take down pin, limiting upper rocking motion, accurizing weapon. Identification Mark, sequential never repeated number engraved before anodizing. Engraved FIRE/SAFE. ALL PINS,SCREWS ENGRAVING INCLUDED.