Sea to Summit Delta Insulated Mug, Pacific Blue;

This mug features a groundbreaking advancement in thermal insulation. Sea to Summit use an integrated molded Polyurethane sleeve that insulates the liquid inside the mug, unlike double-walled mugs which only protect your hands but don't keep your beverages hot or cold. Excess liquid flows back into the sipping hole because of the concave design of the lid. Please note that Delta products should not be used in a microwave