Choose from all of the available Mercury Replacement Brushes & Pad Drivers above. All Mercury Floor Machine brushes ship free to anywhere in the contiguous US 48 states. The brushes fit all Mercury Floor Machines. When purchasing floor machine brushes, you should buy 2 inches smaller than the apron size. For example, a 19 inch floor machine should use a 17" brush. The only exception is Mercury's 20 inch floor machines. The 20 inch Mercury floor machines are actually 21 inches and thus, should take the same brushes a 21 inch machine would take (19" brushes). If this confuses you, please call 888-503-7937 and we can walk you through it.