Kit of Upper and Lower Plungers, Retainer Pin & Hammer Spring for your Mainspring Housing. Gov't / Commander kits supplied with 23 lb. Wolff Hammer Spring. Compact / Officer kits supplied with 25 lb. Woldd Hammer Spring.
If you are replacing one of the Springfield ILS Main Spring Housings that has the little round lock showing in the upper left corner of the MSH, you'll need one of these Completion Kits for your new MSH, as the old ILS parts are different sizes.