For an instant upgrade to your government 1911 pistol, Nighthawk Custom's Drop-In Series mainspring housing provides improved durability and aesthetics over plastic and MIM stock offerings. Each mainspring housing is Fully Machined from billet material to provide unmatched durability. To improve grip on the pistol, 25 LPI checkering has been added by expert gunsmiths. Experience the Nighthawk Difference with the highest quality drop-in parts available.FeaturesMay require minor fitting.416 Stainless SteelGovernment25 LPI CheckeringFlat (Straight) Back