Hi Graham,We use the North extensions you mention here at Team Qsw Windsurfing. Not sure of your question?give us a message back or contact us, as I would be pleased to answer any questions regarding North products . Jonny Utah.
The North Power XT extensions simply make rigging and tuning your sail fast,easy and precise.The main plus for me is being able to experiment and tune my sail either on or off the water by just a couple of clicks on the handle,without having to come in unplug the board,sit down undo all the yards of rope and strain at the hands and back just to set the sail or try something different.
On a" negative" if it is one? they are a mechanical device with moving parts so require careful use! as long as you wash out and store dry and salt free,check the rope regularly and only replace with Norths XT Rope you won't have a problem.All the parts that I have broke(my fault both times)are available From North who have been really helpful.
I won't go back to a regular Extension and run the risk of sitting in God knows what whilst rigging ever again.Hope this helps? any further queries look us up at QSW.
Jonny Team QSW Windsurfing Norfolk