Made entirely of durable silicone. the 300mL Silicone Lid is a cover designed to transform the Ti-double H300 Stacking Mug. Ti-Single 300 Cup.  Ti-Double 300 Mug. Stainless Steel Mug 300. and Shimo Coolers into travel-safe beverage containers and to protect from dust and debris. The snug fit secures easily onto the top of the drinkware with an open lip for drinking and insulating hot and cold beverages.