Hydro Flask Hello, one-handed hydration. More hydration for more fun with our leakproof, Flex Straw Cap. Our 21 oz Standard Mouth with Flex Straw Cap is just the right size for staying hydrated before, during and after activity. Beverages stay cold for 24 hours. The Flex Straw Cap is leakproof and makes it easy to sip on the move. Please note: The way in which the Hydro Flask can be used will change due to the straw lids conditions of use. Our straw lids are designed to be used with cold liquids only. Storing of carbonated liquids in this configured Hydro Flask can create pressure build up and affect the straws ability to remain leak proof. Product Benefits Flex Straw Cap makes cold refreshment that much easier Flex Straw Cap is leakproof when closed, to transport without worry Flex Strap is easy to transport and comfortable to carry Honeycomb ™ Insulated Cap Insulated Cap for maximum temperature retention Made with 18/8 pro-grade stainless steel to ensure durability, pure taste and no flavour transfer TempShield ®️ double-wall vacuum insulation keeps beverages cold up to 24 hours Color Last™ powder coat is dishwasher safe, keeping your bottle slip-free and colourful Dishwasher safe BPA-Free & Toxin-Free Free from toxins, free from worry Care and Use Not for use on a stove, in a microwave or freezer. Not intended for use with carbonated beverages. Flex Straw Cap not intended for use with hot liquids Keep hot liquids out of the reach of children.