I urgently prepared this for winter mountaineering, but the size didn't fit, so I only used it 2-3 times for transportation when going snowboarding, without using it in the mountains. It can hold boots andウェア (wear/clothing), and also attach a board. I bought it quite a while ago, so I don't know the exact size, but I think it's around 50L. The rubber is starting to tear due to aging. Please check the last image. Otherwise, it's in good condition. There are two zippered mesh pockets on the back opening, a long, thin nylon pocket (for a probe?), and a hydration hole. In the fifth image, there's a pocket on the bottom right with a nylon belt stored inside, but I don't know what it's for. #Zack (Backpack) #Ryukku (Backpack) #Backcountry