That's why I was wondering, I could only find one other thread on them here and there was no answers. Luckily my research led me to the Big Squeegee and I will probably be going with that.
I have never seen anyone use these, professional or otherwise.
Is that just foam wrapped around the edge of the aluminum?
If so you can make this thing out of standard extrusion for about a tenth of the cost.
\If you want to try it out before you buy, I'm sure the gas station would let you borrow one of theirs.