GM 1911 Plain Mainspring housing with MagWell in Stainless Steel. It includes a Bar stock machined Mainspring housing & MagWell, CNC Machined parts from Stainless Steel Bar stock, NO-MIM. These are Top Quality Professional Series Parts; Made from the best materials and processes available in today’s market. 2 piece Dovetail base well with set screw. This is a Pro-Series Plain mainspring housing. All Machined from Stainless steel bar stock and great looking and feeling plain back pattern. These are as nice as they get. Will work for full size and commander size 1911 pistols.