The type of backpack that you choose for a trip is very important. Each pack has a specific function that can make a huge difference when you are out on the trail. The main two categories of backpacks are external and internal frames.
External frame backpacks are the original design of backpacks for camping. They have an exposed metal frame that the nylon pack is attached to. These packs allow for a great range of versatility because the exposed metal bars of the frame give room to strap more items on that may not fit inside the pack. It is usually only necessary that half of the people in a larger group have these packs because they can store the odd shaped items that don't need to be carried by everyone. These packs are for carrying tents, kitchen utensils and multiple sleeping bags. These bags are not quite as comfortable and are more bulky, but they have the greatest versatility of any other bag.
Internal frame backpacks have metal supports that are sewn into the fabric of the pack. It is usually made up of about three metal slats that are formed move the weight of the pack onto the shoulders and hips. Many people refer to these types of backpacks as