Hydro Flask is the expert in insulation. We were the first to bring an all insulated bottle line to the market and we continue to focus 100% on double-walled, vacuum insulated products. TempShield Insulation is our unique way of applying vacuum insulation, which ensures that temperatures remain cold up to 24 hours and hot up to six hours, providing our customers with refreshment they can count on, each and every time. Our Flex Cap for our Wide Mouth bottles is ergonomically engineered with wide, flexible TPU material for comfort, stainless steel pivots that allow the strap to move when you move and Honey Comb Insulation that locks in temperature longer.