Very Victorian in feeling. Center flat section is 18mm, you'll need five to six to make a bracelet----usually til you figure in the jumps to connect and the clasp (generally I use either a lobster connected by several jumps or a nice round box clasp). They are about 35mm square, brass base, brass ox plating. Sold by the piece. If you scroll back 5-6 pages in my blog, you'll see a lovely bracelet that I made with these plaques, it went together in about a half an hour and looks like a million.