heavy chain link, thin brass plating. I got the 2 1/4" length chain links and the dimensions advertised are fairly accurate. The link is not quite 1/4" thick, I measured 2.45", but 0.05" is probably within a reasonable tolerance. The brass plating is quite thin and yellow-green in color. I tried applying a dark brown patina, and then relieving it with scotch brite, and that process completely removed with plating, so I recommend not using anything abrasive on it. If you need to open a chain link be prepared for a tough job. I placed the link over an open vice jaw, and then pounded a conical steel mandrel down through the chain link to spread it. It required many hammer blows to get it open.