Made of food-grade safe PE material, this hydration bag is foldable, flexible and reusable, lightweight, reusable, and has a long service life. Easy to fill and easy to roll up. Each water bottle comes with a metal clip designed to attach the water bottle to a bag, bike, or belt, making it easier to carry throughout the trip and less likely to be lost. The push-pull cover and protective cover provide a leak-proof seal. The ultra-light water bottle is perfect for staying hydrated and refreshing while hiking, camping, jogging, biking, or traveling. Simply air dry, flatten and roll to store between uses. Mark the white labels of water bottles with categories to identify them.