All Bentley brushes are flocked.
No Bentlys do make a mono brush, I've got one too. The brisles are quite course, but do an excellent job. I was using it again today on Conwy Marina. The painters have been roller painting the walls in the wind, tiny spots of paint on the glass.
This brush removed most of then. Mind you I was using it for bottoms only and able to put plenty of pressure on the brush. I use a Bently flocked brush for the tops, but may change for the mono one on first cleans, or really dirty glass. Dai