Pottery Supplies Tsuk - Size: 10.7cm - Size: 4cm - Shape: Blocks with curves and straight lines - Quantity: 10 pieces each, 20 pieces total Thank you for viewing. The 4cm ones are new. Regarding the 10.7cm product: Bisque firing (800°) used 5 times for 16 hours each Glaze firing (1220°) oxidation firing used 6 times Although there are some minor imperfections, they are still perfectly usable as they have not been used in reduction firing.