A must for anyone that has Water Bottles! These not only protect your bottle but you can swap up your look! I have found this helpful as mine rolls about our Ute tray at times 🙈 These fit 500ml & 700ml drink bottles, see the last pic I have used as they fit a variety of different bottles,Tupperware, Steel, Plastic and glass. These also have a strap. it can be tucked in if you wont use it.