Assault packs typically known as a Back Pack or patrol sack,which is suitable for patrols and short trip.The assault pack is probably the best seller in the medium range. Also the packs come in two main types.The patrol sack or rucksack and the Mollle style. They have numerous compartments with padded shoulder straps Weight is distributed weight evenly through the pack. These assault packs are very popular with the military.The backpack is a day pack. Day pack means to some kind of pack that we use to contain stuff that will be used during the day and not really used for long trips and are mainly in the 25 to 45 ltre range