This is a cold-water hood made by MOBBY'S, a major diving equipment manufacturer. It's designed for use in cold waters like those off Hokkaido and the Sea of Japan. I've used it about three times, but I'm selling it because I no longer have the opportunity to use it. I was able to dive comfortably even under the ice floes. The size is custom-made, but it's equivalent to a size M. I've attached a picture showing the measurements, taken with stuffing inside the hood for reference.