"Imagine" Sand Castle - Stone Car Coaster Cupholder. Round Car Coaster. This is an absorbent stone coaster that features a sand beach background with a large sand castle and the ocean in the distant view. It has the word, "Imagine." It measures about 2.625" in diameter x .3125" thick and fits most car cup holders. Having a small coaster like this is a great way to protect your car by catching the drips before they run off of your drink and onto your car upholstery!