I bought this rare, large ATACS FG camouflage military backpack at a large military shop in the US. I don't think you'll see this in Japan, but I think it will be highly effective camouflage for airsoft or bird watching. The size is approximately 50cm (height) x 30cm (width) x 20cm (depth), and it's 55L. It cost 550 USD when I bought it. The fabric is a water-repellent, ripstop broadcloth, and the back has a sturdy construction with thick padding and a shape-retaining board. Features include a variety of MOLLE systems, a front cable system for attaching helmets or boards, a lower cable system for attaching tripods, hidden pockets, zippered pockets on the left and right for folding umbrellas or water bottles, and shoulder straps with a hose outlet for a water bag in the main pocket, all designed for compact travel. I think it weighed about 1-1.5kg. What's special about this backpack is that the MOLLE system uses laser-cut camouflage fabric instead of solid-color tape, which significantly expands the camouflage pattern and enhances its camouflage effectiveness.