Durable Lightweight Hydration pack, made with 600D Polyester. Come with a removable 3L TPU, FDA-approved high grade upgraded water bladder. The Bladder has a large opening for easy cleaning and filling and an on-and-off value to prevent leakage. This Backpack also has adjustable front and shoulder straps to keep it securely placed on your body. Plenty of space for other accessories in addition to water!