This all silicone 12 oz cup is 100% European grade silicone with an embedded stainless steel ring. It wont collapse when gripped. The all silicone straw top and straw inserts for a tight fit and all parts are dishwasher and microwave safe. Silicone cup that holds it’s shape, no collapsing mouth.Silicone top inserts for a tight fit.Can be boiled to sterilize.100% silicone and 100% stainless steel.Dishwasher and microwave safe.