The 1045 is a dedicated 45 ACP GLOCK magazine fed AR-15 billet lower receiver. It features last round bolt hold open. Last round bolt hold open on an empty magazine (LRBHO) Flared magwell for faster reloads Accepts 45 ACP GLOCK(R) magazines Integrated, oversized trigger guard Machined from 7075-T6 billet aluminum with a matte black hard-coat anodized finish Requires upper receiver with an oversized ejection port for proper ejection Threaded bolt catch screw For use with a 45 ACP bolt carrier assembly and a standard AR-15 hammer Lower weight: 10.8 oz Patent pending Accepts all aftermarket Glock(R) 45 ACP double stack magazines