[mufcglen]

if your hitting edges with the supreme pal it will be much worse with an xline, i bought a flocked and every time i wiped across the sills the black plastic stock was scraping the plastic.
sold the brush after a few days and went back to the supreme!

[NWH]

I can't understand how your doing that are you not cleaning them from the side at an angle,I find doing it this way the stock dosent hardly touch the sill.

[mufcglen]

not sure pal, all i know is with the supreme for me personally i found because it had a smaller backing and rounded too it was easier wiping across the sills without any issues, with the wider backing of the xline and extreme brushes too i recently found as well scraping the sill.
maybe it was due to the angle i been using the neck on the pole but thats just the way ive always worked and never seemed to have any issues even with a superlite years ago!
one thing im thinking is the bristles stick out the brush in a straighter position than the supreme, the supreme seemed to angle outwards a tad more?
ive got a pic of them side by side and u can see the difference between the two angles im talking about!

[mufcglen]

heres a pic of them side by side and how the supreme brushes just edge out a wee bit more!