Double-Wall Insulation: Environmentally friendly food grade material, double layer insulation structure, can keep water or beverages warm and cold for several hours. No odor, no transfer of odor, no sweating.Washing Instructions: It is recommended to wash by hand with clean water ...Double-Wall Insulation: Environmentally friendly food grade material, double layer insulation structure, can keep water or beverages warm and cold for several hours. No odor, no transfer of odor, no sweating.Washing Instructions: It is recommended to wash by hand with clean water, do not use alcohol-based detergents, so as not to damage the pattern.Material: Inner layer of 304 stainless steel and outer layer of 201 stainless steel, with PP lid.