Mercury Floor Machines 1704 17 inch Stiff Poly Scrub BrushMercury Floor Machines 1704 Genuine Mercury 17 inch Stiff Poly Scrub Brush with "B 92" Clutch Plate Brush is 2" smaller to fit the machine, title is for machine brush fits. The Stiff Poly Scrub Brush is great for economical general scrubbing. Works great on medium to heavy soils on concrete and coated floors. The Clutch Plate attaches brush block to the machine. It is a B 92 durable plastic plate with a standard 5 inch center hole which is able to fit