Nice looking quiver there.
Have u broken yr new board in yet JB - are you enjoying it. I caught up with Chrispy the other day and his board is an absolute beauty in the flesh.
They're Power Base fin boxes. Muzz is now swearing by them for their drive (when using the power base fins) and he hasn't steered me wrong yet so I decided to give them a go. A quick google and you'll find their site.
Can't wait to get the 5'9" in the water, shall be interesting.
Follow this link, it describes the technology but the board in my pic is a different shape/model to the one describe in the link.
www.bourtonshapes.com/presenting-the-scarper/