The Hydro Flask Wide Mouth Flex Replacement Cap helps you quench your thirst on the go – whether at the beach, on bike rides, or during winter mountain hikes. The cap moves with you thanks to stainless steel hinges and features practical, flexible straps. Additionally, the lid is equipped with Honeycomb Insulation™, keeping your cold drinks cold for up to 24 hours and your hot beverages warm for up to 12 hours, regardless of the outside temperature.