This set of 30-piece 20mm ceramic ring sizing pellets is what you need to ensure that the rings made from PMC and other metal clays will maintain their sizes and shapes during firing. These ceramic ring sizers do not burn nor shrink during sintering. When the PMC or metal clay sinters, it shrinks around the pellet, making the ring molds to the precise diameter of the pellet.Why risk incorrect shrinkage with your PMC rings when sintering and why spend money on disposable pellets when this set of 20mm pellets can be used again and again. Quality made in Japan.These 20mm pellets are excellent for standard size rings and bands. With this set of basic ring sizes from one to thirty, you can definitely fabricate rings to their right sizes and shapes. Unlike other products, these pellets are reusable and durable. To use this x30 Reusable Ceramic Ring Sizing Pellets Firing PMC Silver Art Clay Rings 20mm, simply wrap the pellet in a ceramic tape, and to hold it in place, an adhesive tape can be used before placing it inside your PMC ring. Then, you can put it in a kiln for firing. Once the firing is complete, allow it to cool, before removing the dried PMC ring and the pellet for later use.The sizes printed on the pellets are Japanese sizes (sizes 1-30), please see the table below for approximate equivalent sizes.United States, Canada United Kingdom, Ireland, Australia, New Zealand India, China, Japan, South America Italy,     • 1, B, 1     • 2, D, 2, 1.75     • 2½, E, 3, 3     • 3, F, 4, 4.25     • 3¼, F½, 5, 4.75     • 3¾, G½, 6, 6     • 4, H, 7, 6.75     • 4½, I, 8, 8     • 5, J½, 9, 9.25     • 5½, K½, 10, 10.5     • 6, L½, 11, 11.75     • 6¼, M, 12, 12.5     • 6½, M½, 13, 13.25     • 7, N½, 14, 14.5     • 7½, O½, 15, 15.75     • 8, P½, 16, 17     • 8½, Q½, 17, 18.25     • 9, R½, 18, 19.5     • 9½, S½, 19, 20.75     • 10, T½, 20, 22     • 10¼, U, 21, 22.75     • 10½, U½, 22, 23.25     • 11, V½, 23, 24.75     • 11½, W½, 24, 26     • 12, X½, 25, 27.25     • 12½, Z, 26, 28.5     • 12, 3/8, N/A, 27, 29.75     • 12, 3/4, N/A, 28     • 13, 1/8, N/A, 29     • 13, 3/8, N/A, 30No English instruction available.