Stainless mug with non stick coated interior and flip open lid Tight fitted flip open lid keeps beverages hotter or colder than travel mugs Safety lock to prevent the lid from opening accidentally Stopper disassembles for thorough cleaning Wide mouth accommodates full-size ice cubes Zojirushi's stainless steel vacuum insulation mug will keep your beverages hot or cold for hours. The compact design takes minimal space while maximizing capacity. Each flip lid is tightly fitted for excellent heat retention and features a safety lock to prevent accidental opening. Durable and sanitary these mugs have a stainless steel interior with non stick coating for easy clean up.