The Mariposa 60 backpack is Gossamer Gear’s bestseller. Here are my thoughts and first impressions. With a 35-pound weight and 60-liter capacity, it passes the bar for winter backpacking. It has a removable internal frame, 7 pockets, a comfortable hip-belt and shoulder straps, and weighs only around 2 pounds. You have a choice between small, medium, and large and you can configure the hip belt size as needed.