I didn't know quite what this was when I found it, I just loved its weight and surface and the shape of the cutout out, with ribbed areas at four points giving it a bit of tooth! It is marked "NYE Skip Tooth 1 1/2"" and also NYC Tool Machine Works" and so I've figured out is a Skip Tooth Die, which from what I can tell is basically a cutting tool. Also from what I can tell, this is a pretty old one, earlyish 20th century I believe.
3 7/8" x 3 7/8" x 7/8" and in very good condition. It looks more like iron to me than steel.
