Yep, another Rubatex thread. Rubatex GN-231 is nitrogen-blown, and is generally much higher quality than the typical chemically-blown neoprenes used to make most wetsuits today. What that means is it compresses MUCH less, so it retains insulation value better, and it lasts 5-10x as long. There's a video floating around that shows Rubatex versus chemical-blown neoprenes in a pressure chamber.