Bullseye Glass claims these are the best slumping molds they have ever found. They are imported from Creative Ceramics in Europe. The molds are slipcast from a specially formulated clay body, they have an exceptionally smooth surface, accept kilnwash uniformly, and do not crack under repeated usage if handled properly. Diameter, 8.9 x 0.4 in (23 x 1 cm); inside, 4.9 in (13 cm)
Note: The measurements given here are for the outer dimensions of the molds. This is to help you determine whether a given mold will fit in your kiln. Since they are handmade, individual molds will vary in size. Never cut glass to fit until you have measured your mold.