This is a medium ruck sack that is used in the US Army. The Army uses these medium ruck sacks for extended operations in place of the assault pack and large ruck. The bag is able to carrying everything you need for up to 36 hours of hiking, hunting or camping. There is a large main compartment with two 100 oz hydration bladder sleeves and another sleeve for larger, flat items. There are two exterior compartments with organizer pockets as well. You secure all compartments closed with heavy duty zippers. On the front and sides is MOLLE webbing for additional pouches and accessories. There is a hook field for attaching ID patches. The ruck has an external frame that is removable and adjustable padded shoulder and waist straps.