Hydro 12-24oz boot/2.83inch diameter--It was designed for Hydro Flask Water Bottles 12oz 21oz 24oz wide mouth and standard mouth. Extensively compatible with Stanley Adventure Quencher 40oz and Stanley IceFlow 20oz 30oz Tumblers and other brand water bottle with bottom diameter 2.83inch SMART DESIGN - Try more colors/Designs, mix and match to dress up your favourite Hydro flask water bottle. Warning: silicone boot only, flask water bottle is excluded. Food grade silicone material - Made of high quality food grade silicone material, it is safe, soft and a bit stretchable, easy to put on and take off for daily use PORTABLE TO CARRY – Reusable, durable, foldable and dishwasher safe. Our sleeve can withstand stretching, folding, and anything life throws at it.