BOROSILICATE GLASS - Will not crack under extreme temperature changes like regular glass. UNIQUE DESIGN - Inspired by Mt. Fuji in Japan, the beautiful mountain rises from the bottom of the cup to be surrounded by the liquor within. DISHWASHER SAFE - Place on the top rack of dishwasher to wash and clean. MANY USES - Use it for cocktails, Bourbon, Scotch Whiskey, Cognac, Wine, water and juices MANY USES Handmade, crystal clear, high quality borosilicate glass, that will not break from extreme temperatures. Thickened bottom for greater stability and strength. Perfect for cocktails, water, tea or juice. The beauty of the multi-color cup comes from the colorful play of light that is reflected from its surroundings.