Hydra pack portable pocket-sized hydration This water bottle is very lightweight and durable, with minimal design for packing. Spillproof nozzle is spill-proof and easy to drink during activity. The cap diameter is 1.1 inches (28 mm), and is highly versatile. Comes with a handle, so it is convenient to carry and fill with water. The handle can also be stored very compactly after use. Includes flip top cap to keep drinking spout clean With a divider on the inside of the 3.3 gal (1 L) does not overinflate even if filled with water, so it is easy to hold. Packable: Minimalist design and very durable. When you are finished drinking, you can fold it up small and take it home. Flip Top Cap: Easy to open and close and comes with a cap that keeps your mouth clean and protected. Highly compatible cap: 1.1 inch (28 mm) diameter is widely used by many water purifier manufacturers. EASY TO CARRY: Soft and durable lightweight handle for easy carrying. It is also convenient to fill with water.