The YHM lowers are machined 100% in house from forged 7075-T6 aircraft grade aluminum. They feature over sized magazine well chambers for easier magazine changes. They will accept all generations of PMAG's and mil-spec upper receivers. They fit all standard parts and are finished in hardcoat anodized matte black to military specifications or better. NOTE: Requires a lower parts kit, buffer & stock of your choosing to complete. Type Stripped Finish Matte Black Hardcoat Anodized Series Lower Receiver Caliber 5.56x45mm NATO Trigger None Gun Type AR Platform Material 7075 T6 Aluminum Gun Model AR-15