Stainless steel vacuum insulated construction with superior heat and cold retention; Heat retention: 138°F @ 6 hrs.; Cold retention: 50°F @ 6 hrs. Flip Lid with safety lock prevents the lid from opening accidentally; Leak-proof, gasket-free, one-piece lis is easy to clean and prevents the loss of parts Lid is designed to minimize condensation from forming SlickSteel polished stainless steel interior minimizes odors and stains High quality 18/8 stainless steel, Made of BPA-free plastic and stainless steel