I know this is a year later, been having some issues with the ski so not had it out until now so just reporting back on this device,
Great device, very easy to install and set up and the manual is clear.
On the water it takes a split second to give out a reading but is consistent unlike the paddle wheel which only works if the ski is in the water ( every time the ski jumps out the water the paddle wheel doesn't spin and therefore the reading is always up and down.)
But yeah, all in all a great little device, only down side is that it's quite expensive for what it is.