Ultrafina seems to be quite full of fillers.
Just an add on from the original range. They used to have a finishing glaze/machine polish.
My point is clay has only been around for a short while,
I'm machining mine this weekend, today I had the car on the ramp after a good g101 decreasing wash, on the ramp I've cleaned the panels with atomized tardis, the panels, door shuts and under sills are now free from any debris, in left with a virgin paint surface to work on.