Ideal for extended trips and adventures
If you're heading out for a long, extended backpacking trip or climbing expedition you will probably need a larger backpack to haul all of your gear. And the reason for this is because you'll probably have more gear to haul if you're going on a trip that lasts several days.
Most expedition/travel packs are made with larger storage areas that allow you to pack enough gear for your trip. Most of these backpacks have capacities of at least 70 plus liters or just over 4,270 cubic inches. Most of them are also designed to handle loads of 50 pounds and more. To be able to do this they usually have relatively stiff internal frames for strength and plush suspension systems to help keep you comfortable.
Although these backpacks are ideal for backpacking trips of a week and longer, they're also ideal for shorter trips in the spring and fall trips when you may need to take along more clothing to keep warm.
Expedition/travel backpacks are generally made out of lightweight, but strong and durable fabrics such as ripstop nylon, and they are often reinforced and/or coated to help keep the backpack dry. The backpacks have either top/side loading or panel loading and most of them come with external sleeping bag compartments. The hip belts and shoulder belts are usually padded to help you out in the comfort department. Some models even have heat molded, foam belts and straps to give you a custom fit and load adjusters to help you disperse the load evenly.
Just about all expedition/travel packs are hydration compatible, and some of them will have a system included. Some packs come with removable daypacks and some have sections that can convert into lumbar packs. The backpacks will come with varying numbers of pockets and compartments and may also have safety whistles, ice axe loops, daisy chains, tool loops, bungee cords, and lash on points.
You'll find that expedition/travel backpacks come in a wide variety of sizes, colors, materials, sizes, and designs. They can be quite a bit bigger and heavier than a general backpack, especially when they are full, so it's a good idea to only use one when it's necessary as a half full expedition/travel pack would be wasting valuable space and can also be quite awkward to balance and carry.