Our coasters are made of tin and cork. Our coasters have a raised edge on the top designed to keep a glass or mug from sliding off and to catch any spilled liquid. Our coaster's bottom is made with cork to create a non-slip surface, which prevents it from sliding around on smooth tabletops, this protective layer also offers several other benefits, including absorbing moisture and preventing scratches. Made in Turkey Ships from Orlando, FL Dimensions; 3.5" x 3.5" (9CM X 9CM)