Angstadt Arms 0940 Lower Receiver is machined from 7075-T6 billet aluminum with a matte black hard-coat anodized finish and works with any mil-spec upper receiver. It features a flared magwell integrated oversized trigger guard and a last round bolt hold open. The 0940 lower receiver is compatible with Glock magazines. The Lower Receiver Set features a upper receiver with appropriately sized ejection port and no forward assist or dust cover