I`ve just got hold of 2 salmon brushes that are mono crinkled medium grade bristle,they seem quite stiff but when wet seem to soften up a bit.I know like me your always trying new brushes but i`m worried about it scratching glass,it`s like the 15" one Jouk used in his car jet demo only it`s medium grade so slightly stiffer,i know some people have said if your no careful you can scatch car paintwork with them.