Leather BackPack The GearMax® “M” Series expandable back pack looks and carries like a conventional back pack, yet opens to a portable locker allowing easy access to contents. The hanging hook quickly attaches to a door, locker, tent, or tree, and allows the bag to hang open. This bag is a great transition bag for triathletes with compartments for helmet, biking shoes, wet swim suits etc. Also, great for a school backpack for kids, camping, traveling and other back pack needs.