saltyheaven said.. I've got an old F2 one. Not sure I'm very keen on the whole slidy thing....
My dakine slider wore out, so I used a fixed one for a few years. It's horrible, you can't face your body the right way. Back to a slider now, sooooo good.
Once you use a harness with a sliding hook,there is no going back!
I agree,with a fixed hook it's so hard to twist your body for the correct technique.
In really strong wind a sliding hook has a huge advantage in that you can get more to much more of your upper body weight to the nose to to keep the board down. This technique of maximum weight to the nose of the board also helps sailing upwind.
I really struggle with a fixed hook in anything above 20 knots.
DaKine NRG has a slider conversion that is available for about $15 (USD). It's just a piece of webbing 1 3/4" x16" long with rectangle rings at each end that fit the bar hooks on the harness. The narrower your bar is, the more slide you can get out of it. Works pretty well, but they can wear out, so buy 2 or 3 of them.