This Tumbler was created for comfort with ingenuity. The indention fits well with your thumb -creating the sensation that the cup is more an extension of your hand rather than a piece of drink-ware. Please send our apologies to the other glasses in your cupboard. They are going to be jealous of how much you use your Dented Tumbler. Each one is handcrafted with lead-free materials, safe for both the dishwasher & microwave and holds up to 10 oz.