OUTAD Hiking Daypack 40L Waterproof Internal Frame Backpack Hiking Backpack For Outdoor Hiking Travel The Suspension System is removable. It is extremely flexible and can easily adjust to the back shape 420D Polyesterfibre: waterproof and scratch resistant, more durable. Provide a cable entry(you need to cut it out). Use for the earphone line and the tube of water bag, Color ranger: Army Green, Red, Blue, Black. Provide a rain cover which is suitable for the backpack. And a whistle for asking for help