Fusion Firearms, 1911 Officers Chain-link Mainspring housing MagWell in carbon steel, Matte finished. It includes a Bar stock machined Mainspring housing & MagWell, CNC Machined parts from Carbon 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 Chain-link pattern mainspring housing. All Machined from Carbon steel bar stock and great looking and feeling cut chain-link pattern. These are as nice as they get. Will work for most all Officers size and Many Micro style size 1911 pistols.