These coasters are 3/16" thick stainless steel, cut with a waterjet machine. They will not rust or discolor, have a nice heft to them, and the edges are crisp but the pieces have been processed in a tumbler and there are no sharp corners. The raw metal finish has a satin gloss, with a fine grain texture.
Fit together, they work great as a trivet or under a potted plant. 4 individual coasters per order. Made in North Carolina, USA.