The MKM Pottery Tools Decorating Disk is the ultimate measuring tool.
Each of the two disks has its own even- or odd-segmented divisions. Colored radial lines allow you to create even divisions by 2, 4, 6, 8, 10, or 12 on one disk, or odd divisions by 3, 5, 7, and 9 on the other.
Concentric circles allow you to quickly center your piece.
Along the radial lines are holes that allow you to mark through the disk to the clay, whether it is soft, leather-hard, or even bisque-hard.
Use it to mark your bats or wheel head, alter a rim around a bowl, or line up your handles and spouts.