Evolution Gun Works Officer's Mainspring Housing Magwell Combo 1911s Colt Defender Stainless Steel Glass Beaded Finish Stainless. This product fits:Officer's Model 1911sColt DefenderPins and springs do not come with this part. You can use the pins and springs from your original mainspring housing or purchase new parts from us.Our premium msh/magwell combo is machined from barstock and held to very tight tolerances. The mainspring housing has a t-slot cut that accepts the magwell. The fit between the two parts is very tight and might require a small tap with a hammer. The width of the mainspring housing is slightly oversized which allows for a tight fit in the frame. This eliminates any type of wobble or play from the msh/magwell. Specifications for Evolution Gun Works Officers Mainspring Housing Magwell Combo: Manufacturer: Evolution Gun Works Fabric/Material: Steel Design/Pattern: Checkered Gun Make: 1911 Platform Condition: New Package Contents: Evolution Gun Works Officers Mainspring Housing Magwell Combo What firearm models does the manufacturer say Evolution Gun Works Officers Mainspring Housing Magwell Combo is compatible with? The manufacturer suggests that Evolution Gun Works Officers Mainspring Housing Magwell Combo is compatible with Colt 1911 1911 DefenderEvolution Gun Works 11422: Officers Mainspring Housing Magwell Combo 1911s Colt Defender Stainless Steel Glass Beaded Finish Stainless