Comfortable: adjustable shoulder straps with nuclear chest strap, specially extended chest and waist straps, also suitable for adults with growing physique. Eco-friendly: 2L hydration bladder, tested and certified BPA free. smooth inside of the bladder, less likely to cling bacteria and easy to clea Capacity: size 44cm*25cm*12cm, 1 main zippered pocket for clothes and water bag inside the backpack; 1 front zippered pocket for mobile phone, wallet, etc. There are also 2 mesh pockets on the side. Details: High quality nylon material, durable and water repellent. There are several reflective stripes, whether riding, running or hiking outdoors, making it safer to travel at night. AFTER-SALE: If you are not 100% satisfied with our water bags, we will refund your purchase price - no ifs, ands or buts! Get ready for your next adventure now!