These Silicone Donuts are made from a new type of silicone that is so stretchy and soft to the touch you will not believe that it is silicone. This three piece set is so comfortable you will never want to take it off. Use one, two or all three. They make great ball rings as well. Each set includes one 40mm, 45mm, 50mm. Buy more than one kit at this price and make a cool ball stretcher too.