Perfect. Its either those or the Blick 4.25 inch square bisque ceramic tiles (found a link to those on here somewhere) as frag disks to place on my BB glass.
They also have the stone travertine 12"x12" tiles that have 144 1"x1" squares for small sps frag nubs or zoas. They have the mesh on the back you can cut with a razor. Makes the plug about 5-10 cents a piece.