This thermos mug is a high-quality choice: made from stainless steel, it is built to withstand everyday use for years. The Flex Sip Lid can be swapped for another compatible lid from the same manufacturer, as long as it fits the widemouth size. Thanks to the premium materials, no flavors or unwanted substances will transfer to your drink. The mug keeps drinks cold for 24 hours and hot for 12 hours. - Stainless steel construction with vacuum insulation - Leak-proof lid - Flexible carry loop on the lid - BPA- and phthalate-free - Dishwasher safe Do not place your HydroFlask in the microwave, freezer, or on a stove or cooktop.