Designers at Osprey are no strangers to setting the bar high for lightweight backpacks, and the new Ariel Pro 65 Women's Backpack proves it. It packs in a whopping 65-liters of space, while weighing in firmly under 4lbs -- a pretty remarkable feat for a backcountry ready expedition pack. It does it by integrating featherweight, but durable NanoFly fabric with the new Lightwire suspension system, carving out the perfect combination of support and weight savings to keep you going when you're pushing up near-vertical faces, striving to make it over the mountain pass before dark sets in, so you can set up camp for the night by fireside, instead of with the dim glow of headlamps. To ensure you've got the conveniences when you want them, but not when you don't, Osprey equips the Ariel Pro with tons of removable pockets and straps. If you're going on an ice-scaped adventure, you'll be glad to find the two ice-tool straps with cord attachments, but if you're going for a lightweight summer camping trip, ditch the ice straps and toss on your sleeping pad strap to keep it secured in back. The top lid pocket is zippered for storing gear, but can also be removed when you want to shed weight. In back there are two removeable compression straps that stabilize your load, and reinforced cord loops let you bring along an additional Daylite daypack or Alpine Pocket, so leaving for a quick out and back hike doesn't have to come along with your 65-liter load.