ThermoFlask asked thirsty people, from pro athletes to fitness enthusiasts, how they could make a better bottle to support their active lifestyle. They all gave us the same answer:The lid. Make the best lid out there, they asked.So, they did. They engineered a sustainable food-grade stainless steel bottle with a sleek silhouette and a universal lid system filled with thoughtful, caring design and an unrivaled pioneering hydration technology.