Professional quality monofin. As a scuba diver, lifeguard and ocean swimmer I was only willing to invest in a real ocean quality swimmable mono fin Size euro 40-42 USA women’s 8.5-10.5 This is heavy duty, unbreakable and will last forever. It’s neutrally buoyant and wonderful to swim in. I’m ONLY selling because my feet grew and I wanted a new one in a size bigger! I literally just rebought this same fin!