This popular coaster measures 3.5 inches in diameter. The dark ones are made of walnut and the light ones sre made of pine. Use renewable materials. Durable and elegant. Ideal for maximum brand exposure. The coasters are non-slip. There are two types, one is smooth and the other has protrusions around it to keep liquids from spilling onto the table. Great for giveaways, trade shows, restaurants and corporate events. We can print your logo on the Novolinepromo.com/products.html target='_blank'>products for promotion.