Made entirely of durable silicone, the 450ml Double Mug Silicone Lid is a cover designed to transform the Ti-Double H450 Stacking Mug, Ti-Single 450 Cup, and the Stainless Vacuum-Insulated Mug in 450ml into a travel-safe beverage container.  The snug fit secures easily onto the top of the mug with an open lip for drinking.  To clean, simply remove and wash with any dish detergent before air drying.