Fusion Firearms Mainspring Housing Officers Internals Pin Kit Black. All Precision CNC machined from bar stock and heat-treated with Black Oxide finish. Also includes standard 23 pound(US Gov Spec) Mainspring. All in one kit package. Specifications for Fusion Firearms 1911 Mainspring Housing Pin Kit: Manufacturer: Fusion Firearms Color: Black Fabric/Material: Carbon Steel Gun Make: 1911 Platform Package Contents: Fusion Firearms 1911 Mainspring Housing Pin Kit What firearm models does the manufacturer say Fusion Firearms 1911 Mainspring Housing Pin Kit is compatible with? The manufacturer suggests that Fusion Firearms 1911 Mainspring Housing Pin Kit is compatible with Colt 1911 Government 5in Colt 1911 OfficerFusion Firearms 1911-MSH-25KIT-2: 1911 Mainspring Housing Officers Internals Pin Kit Black