These thick sponges are easy to hold and last long time which still won't feel tired. For working with clay, crafts, pottery and art paints, also great for household or face painting. Easy to wash and clean. They are compressed to save space, will expand with water or exposure to air. Application: works great with acrylics, oils, watercolors and fabric paints or dyes Material: the synthetic artist sponges are made of foam in round shape with smooth edges, soft and not easy to deform, help you finish your work quickly.