Sofft Sponges- Four Round SpongesSofft Art Sponges are made with semi-absorbent micropore sponge material. Each sponge has a unique shape and size designed specifically for artists and crafters. Perfect for applying color blending building up layers underpainting wiping color out... the uses go on and on! Some of the most simple tools are also the most versatile. Perfect for use with Pan Pastels pastel sticks charcoal graphite pencil watercolor and ink. Sponges can be gently rinsed out in warm water and used over and over. This pack contains four round sponges. They have a diameter of 1-15/16 inch and are 1/4 inch thick.