Hydration on the go just got easier with our leakproof, insulated Flex Straw Cap. Add it to your favorite Wide Mouth Hydro Flask bottle to easily enjoy cold hydration anywhere. F Flex Strap Easy to transport and comfortable to carry. Honeycomb Insulation Insulated cap for maximum temperature retention. Leakproof Leakproof when closed so you can reliably sip and transport your refreshment without worry. Easy to Clean Removable components for easy cleaning. S Wide Mouth Flex Straw Cap fits all Hydro Flask Wide Mouth Bottles Straw is easy to trim to fit your favorite Hydro Flask Flex Strap is easy to transport and comfortable to carry Honeycomb Insulated cap for maximum temperature retention Leakproof when closed so you can reliably sip and transport your refreshment without worry BPA-Free & Toxin-Free Removable components for easy cleaning.