Charles Viancin Grape Drink Cover Set/2 Set of 2 4 Silicon Drink Covers in the Grape Leaf design Our silicone drink covers keep your coffees, teas, and cocoas piping hot and your fruit juices, soft drinks, and cocktails refreshingly cool. The silicone construction creates an airtight seal on most glasses regardless of whether theyre glass, plastic, stainless steel, ceramic, or even wood. In addition to insulating your next beverage, our drink covers also protect your precious liquids from winged pests! CHARLES VIANCIN drink covers are safe to use with most appliances including: ovens, microwaves, refrigerators, freezers, and dishwashers.