The ALPS Mountaineering Caldera 4500 is a great internal to take along on all your backcountry treks. The Caldera was designed with features to make your hike more enjoyable. Beyond the easy to adjust suspension system, front and side pockets, and hydration pocket and port, you can also find side compression straps, an internal horizontal divider to arrange your gear, and extra large 10 zippers on the lower door. All of these features will ensure that you're ready for a successful and organized hike. So now you're ready for your trip and your pack is full, but you still have a few things to take along... don't worry! The top of the Caldera pack extends with a spindrift collar, so you can over pack. The top pocket adjusts up and down to keep it in the correct position and we've included an Over the Top compression strap to stabilize your extra gear. When it's time to drop the internal and adventure onto a smaller trail, don't worry about bringing along an additional small fanny pack, because our top lid converts to a fanny pack. If that's not enough, the rain cover is included! You don't have to worry about spending additional money on accessories you can find it all in the Caldera. This internal is a great example of what ALPS Mountaineering is all about... giving you great gear at an affordable price.