It is made from stone absorbent ceramic with a natural cork base. The coaster’s bottom layer is absorbent ceramic stoneware. Each coaster for drinks measures 4×4 inches, making it just the right size for all standard cups, mugs, and glasses. Cleaning your new absorbent coasters is just as easy as using them. Simply rinse the drink coasters in water, and brush it to clean. Dry it in the wind or sunshine. Orders of 1000 pieces or greater are eligible for sea shipping. 100% guarantee for quality.