Narcotic, now I get it, with the whiskers they are 10 percent negative. This advanced technology is better that the rubber band fin. The adjustable wiglets allow you to change the blade performance by using the water flow. Year's ago (1980) I played with some rubber spear gun tubing on the Fab Force, which was a fin made from several types of fabric. The idea was to change the fin blade stiffness by stretching the rubber tubing or letting the pull go making a softer fin blade...but it was still the same surface area moving Thur the water and I was worried the rubber bands would fail over time...and they do. Thinking further I had my friend Bob Kirby ( Kirby-Morgan diving helmets fame) shape me the original whiskers we now use. My idea was to use a wing shaped device that could be used to move and change water flow dynamics. Skin Diver Magazine covered this concept back in the early 90's, yet today it is often over looked as a way to change fin performance. This concept is on several Force fin models. Your a fan, take free shipping and a 15 discount by calling us next week. If your not happy to can always return them for a full refund. Hopefully we can cover more on this Force fin advancement.