MOUNTAINTOP Hiking Hydration Pack Backpack for Cycling Running Bicycle Walking Climbing Camping Biking Bag -PROFESSIONAL CYCLING PACK- 20L (1,222cu in) Hydration backpack for outdoor sports (hiking, camping, climbing, cycling, etc) or traveling. -WATER RESISTANT- This water-resistant fabrics do not allow water to easily penetrate.Keeping your gear dry. -BEARING SYSTEM- Padded and breathable mesh back panel and shoulder straps offer cushioned comfort, while also promoting air circulation along your back and shoulders. -ADJUSTABLE WAIST BELT- can be adjust on both side.Comes with the elastic straps are designed to keep the strap secure and prevent loose straps hanging from the pack. -HYDRATION SYSTEM COMPATIBLE- Internal hydration bladder's compartment and dual Velcro exit ports for the tube (bladder not included).