Earlier in September I had a chance to dive with Peter Scott and check out his new Dol-fin. It is basically a monofin with a high aspect ratio blade. Interestingly, the blade has much the same dimensions as the power blade of my Aqueon. However, unlike the Aqueon, it is very light in weight and low in drag. I think the Aqueon has more power though.
Peter's Dol-fin is a prototype, built by someone in Arizona. So, sorry, you can't buy one yet and I don't have a link to the inventor/manufacturer.
Have a look at the video below to see the Dol-fin in action:
