The hydration pack with 70 oz water bladder from unigear is more than just your average hydration pack. Its 21oz nylon ripstop fabric gives it that extra bit of protection from the elements. A 2 Liter/ 70z BPA-free bladder is included with the pack. Adjustable shoulder and chest straps ensure the group stays in place and does not bounce when you move. Double built-in waist straps are included to improve wear and tear resistance. The nylon material is splash-resistant and lightweight, making it perfect for biking. There is an SBS nylon zipper and reflective webbing, which help you stay visible to motorists on the road.