These are simply the finest slumping molds we have ever found on the commercial market from Creative Ceramics in Europe. 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. Dimensions shown are the largest dimensions of the mold itself, in order to determine kiln shelf size required. Individual molds may vary slightly from dimensions shown. Whether pre-fusing or cutting unfired glass, create your blank to match your mold.