RX-20 Hard Floor Brushes for light duty Suitable for Light Duty (LD) to medium duty cleaning of stone, slate, terrazzo, tile or sealed concrete floors. The brush area is tufted with blue .022 nylon fiber impregnated with 120-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 red pads and blue pads.