RX-20 Hard Floor Brushes for heavy duty Designed for Heavy Duty (HD) and aggressive scrubbing of concrete and aggressive stripping of resilient floors. The brush area is tufted with blue .060 nylon fiber impregnated with 46-grit silicon carbide. 15" Diameter block, Five (5) vacuum pick-up tubes and Three (3) #2 S/S high- pressure solution jets. The brush on this attachment replaces high productivity pads.