I have to admit I was not expecting much as a just received the new H4's. It was rubs description and vision of these new Keel thruster Fins. 1st wave bottom turn straight into a top turn off the lip. I remember thinking The Fins felt like they did all the work. I just held on for a really fun in new experience of a ride. I would describe them as having a lot of hold/driveWith the ability to release a your will. These fins provide a completely different feeling than anything else in the FCS line. Very happy to have these and the H4's. You can believe me because I own Most of the FCS line. The entire Essentials series and select Shaper an athlete Fins.