Blending Tool Sponge Refills are available in packs of four with the hook-and-loop fastening making it simple to swap blending sponges when changing colors or mediums. The refills are designed to work with the Sizzix Studio Blending Tool Set (666784, sold separately). Each Blending Tool Sponge has a diameter of 1 1/4", and can be washed repeatedly to extend its use.