The 1045 is a dedicated 45 ACP GLOCK magazine fed AR-15 billet lower and upper receiver set. Includes last round bolt hold open. Last round bolt hold open on an empty magazine Flared magwell for faster reloads Lower receiver accepts 45 ACP GLOCK(R) magazines Integrated, oversized trigger guard 7075-T6 billet aluminum lower receiver with a matte black hard-coat anodized finish 7075-T6 billet aluminum slick side upper receiver with appropriately sized ejection port and no forward assist or dust cover Threaded bolt catch screw For use with a 45 ACP bolt carrier assembly and a standard AR-15 hammer Lower weight: 10.8 oz Upper weight: 6.5 oz Patent pending Accepts all aftermarket Glock(R) 45 ACP double stack magazines