The double-wall insulation makes the Iron Flask sweat-free! It keeps your drink cold for up to 24 hours, and hot for up to 12 hours. The Iron Flask comes with three different lids. Straw Lid with 2 Straws, Flip Lid and a Stainless Steel Lid! The Iron Flask is made of 18/8 Stainless steel that is 100% BPA free and non-toxic. It will never leave a metal taste or rust. It must be hand washed with hot soapy water!