This 20mm ceramic ring sizing pellet set comes with 10-piece ring sizers. These ceramic pellets are the perfect tools for ensuring that the right size and shape of rings are achieved during firing. These ceramic pellets don't burn nor shrink even when fired. While the PMC or metal clay sinters, it shrinks around the pellet, making the ring molds to the exact 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.Measuring around 20mm in height, these pellets are excellent for standard rings, bands and jewelry. These ceramic ring sizers are reusable and long-lasting, making them a great addition to your jewelry tool kit.To start with, 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 or metal clay ring. After that, you can put it in a kiln for sintering. Once the firing is done, allow it to cool, before removing the finished ring and the pellet for later use.The sizes on the pellets are in Japanese sizes, please see the table below for the approximate equivalent sizes.United States, Canada United Kingdom, Ireland, Australia, New Zealand India, China, Japan, South America Italy,• 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, 18.25No English instruction available.