Coaster diameter ：The set includes 4 round ceramic coasters ( 9.6 cm ),thickness:0.7 cm, suitable for all glass, mug, cup. Well-designed iron holder: the iron holder is made of black metal, stain resistant and scratch proof, and won't get rusty.Black metal holder included to let you can organize coaster. Makes coasters look beautiful and better organized. Non-slip Bottom: The bottom is made of cork, which won’t scratch your tables and other surfaces and provides a non-slip surface. Absorbent ceramic stone coasters will make sure the surface of your coffee table or countertop stays clean and dry when you enjoy the full taste of your drinks cold or hot. Spills can be easily wiped off with a damp rag and should not stain if removed in a timely manner. Use warm water and a mild dishwashing detergent or stone safe surface spray to clean. Material: Natural Ceramic ( cork bottom). Diameter: 3.8in/9.6cm Thickness:0.3in/0.7cm Why choose our coaster? Keep Your Desktop Dry and Clean. Anti-skip cork backing to prevent scratches on the table.