Weighing less than eight ounces it's hard to find a reason not to pack these Celestial Pants from Outdoor Research. This lightweight waterproof and breathable design features complete seam-taping for weatherproof comfort. Articulated knees enhance your range of motion while side zippers make it easy to remove your hiking or climbing boots. Granted it's not what you want to rolling around on abrasive sandstone but if it starts to pour when you're a week away from the nearest trailhead you'll be glad that you rolled them into a side pouch. If you're looking for a similar design for your upper torso check out the Outdoor Research Zealot Jacket™.