Everyone can agree that multi-day backpacking treks and rugged alpine mountaineering missions aren't exactly a walk in the park, but they don't have to bring on the aching shoulders and sore backs that you might be bracing yourself for when you set out from the trailhead, at least not with the Mammut Trion Spine 50L Backpack. Outfitted with Mammut's new Active Spine technology, this pack offers stability, comfort, and a versatile size for an endless range of pursuits in the mountains. With Active Spine, Mammut was trying to find a suspension system that keeps your shoulders and hips happy as you hike, but wouldn't sacrifice the stability of the pack's load in doing so. Their solution was to allow the hips and shoulders to move independently of the pack's body, but to keep the two connected with a flexible spine-like system to ensure that all that movement won't set your load rocking back and forth. The result is an ideal balance of freedom of movement and weight distribution that'll have you cruising in comfort over even the steepest and most rugged terrain. That's not where the innovative design of this pack ends though. It's got a handy pull tab that adjusts the Active Spine system up and down, helping the wearer find the size that's right for them in an instant. For convenience there's a large easy-access front panel that lets you reach inside the pack without having to root around from the top, but if you did want to root around from the top you could, thanks to the top entry system that features a protective flap. With gear loops, compression straps, and lots of pockets, you've got tons of space to bring along all the gear you need, along with ice axe, trekking pole, and ski carries that let you take on whatever adventure you so choose.