These cups' PLA lining is created from corn starches to give your venue an eco-friendly edge. The lining creates a heat-resistant barrier that's able to withstand temperatures up to 200 degrees Fahrenheit. It is waterproof and greaseproof. They are high quality and stylish. Covering multiple sizes 4oz 5oz 6oz 7oz 8oz 9oz 10oz 12oz 16oz 20oz 22oz ect.