Features Multi-Functional Storage: With a capacity of 25L and multiple pockets, 1 main compartment has a separate bladder compartment for a 2 liter bladder (bladder not included), a quick access front pocket with zippers, a helmet pouch, two side pockets, can perfectly meet all your storage need. Comfortable and Breathable: Breathable Mesh padding for relieving fatigue and ventilation that makes hydration pack perfect for men'or women's hiking backpack, becasuse of adjustable chest strap / hip belt, the backpack not only can perfectly fit our back, but can be also fixed well even if you are driving fast or on bumps. Consummate Design: A mesh elastic pocket to carry bike helmet on the go with buckle for fixing helmet. Reflective strips on the front of the water backpack increase visibility and safety when walking or cycling at night. In addition, the connection of the chest strap has a lifeguard whistle that providing the most enjoyable and comfortable experience for hikers and cyclists. Outdoor Companion: This bike backpack is perfect for cycling, hiking, climbing, biking, adventure, etc, will be a terrific companion for your all day-long or overnight hydration needs. Note: Helmet and hydration bladder not included!!! Occasion: Hiking, Camping, Hunting, Fishing, Trekking, Traveling, Climbing and other outdoor activity.