1.Safety backpack: waterproof hydration backpack is made of nylon material, which is wearresistant and tearresistant. The breathable mesh reduces strain and increases comfort. The shoulder straps and back of the backpack are thickly padded to reduce shoulder and back pressure, and multiple reflective strips on the front and back of the backpack increase . Increase when marathon, running in the dark and cycling. 2.Backpack with 2L hydration bladder: hydration bladder has a capacity of 2 litres, which is enough to meet your hydration needs during outdoor activities. The water bag is made of high quality food grade materials, BPA , durable and not easy to leak, so you get clean and drinking water. 2L hydration bladder has a soft straw for easy drinking, so you can refill water anytime and anywhere to keep your body y. 3. and portable: running backpack set contains a backpack and a 2L hydration bladder. The backpack size is 48 x 23 cm, the water bag size is 41 x 17 cm, only 300 g and 120 g, and the hydration pack bicycle backpack is foldable. You can easily carry trail backpack during outdoor activities such as hiking, cycling, mountaineering, etc., reducing the load and allowing you to enjoy outdoor fun. 4.Multifunctional backpack: Hydration backpack with hydration bladder 2L has a water bag compartment and a storage compartment in which mobile phones, wallets, raincoats, outdoor tools and other items can be stored, bungee cords fix the backpack securely in place and allow unrestricted trail running or cycling.