Hydro Flask 20oz Wide Mouth Flex Sip20 OZ - Green Hydro Flask 20oz Wide Mouth Flex Sip - in stock now. The Hydro Flask 20oz Wide Mouth Flex Sip is an insulated bottle for transporting your drink. Coffee is my drink of choice in this Tempshield, double wall vacuum insulated container. You can put some hot chocolate in there if you prefer, or just water if it's a warm day outside. Either way, the flex sip lid is leak-proof, sippable from it and even has a little handle. Hang onto the handle with your hand, or clip it to your backpack. Products on Sale Are Discontinued Styles or Colors. Features of the Hydro Flask 20oz Wide Mouth Flex Sip TempShield double wall vacuum Insulation Stays cold up to 24 hours Stays hot up to 12 hours 18/8 Pro-grade stainless steel BPA and phthalate-free for ultimate purity Proprietary powder coat Flex strap Leak-proof lid Compatible with all wide mouth accessories Lifetime Warranty.