Supergirl 3.75″ Coaster. Drink coasters are a great idea for house warming gifts, offices, home decor, wedding gifts, and so much more. They are a unique way to add a personalized touch to any space! To clean wipe clean with a damp cloth. Made from premium hardboard with a strong, high quality coating. Each of our coaster designs are permanent, and are NOT decals or markers. We use high quality dye sublimation inks to print the coasters, and they they will not fade, crack or peel. All four coasters have a different design on them.