AD 56505203 20" .050"/80 Nylo-Grit Scrub Brush for Nilfisk Advance ConvertaMAX 20, BA 550, BA 5321/D Walk Behind Scrubbers. Our second most aggressive brush in this series. Heavy duty grade grit (.050/80 grit) black Tynex-A or Hahls nylon with 80 grit silicon carbide granules for stripping or heavy duty scrubbing on unsealed concrete, asphalt, quarry tile, terrazzo, or older sealed flooring with heavy to moderate dirt and debris. Commonly called Black Grit, Nylo-Grit, DynaGrit, DynaGrit 80 or Mal-Grit. Replaces brown floor pads. For a more aggressive brush, use the AD 56505201 46 grit brush. 19" diameter block with clutch plate. Fits Advance ConvertaMAX 20, Nilfisk BA 550 walk behind floor scrubbers. One brush required per unit. Sold each. Replaces Nilfisk Advance 56505203. Our Part Number AD 56505203