They are the same binding, just the 18s have a stronger spring, right? I know the 12s have a lot of plastic, and the 15s are all or mostly all metal, so I was guessing the 18s were made the same way just with a different spring. Anybody with the 18s mind weighing them, and if they are on skis could you tell me how much the combo weighs and I can try to find the ski weight. Thanks