FC 40-521N 38" 18 Single Row .016" Soft Nylon Cylinder Sweep/Scrub Brush for Factory Cat 420, 430 Riding Floor Scrubbers. Soft .014" diameter Nylon filament for light duty scrubbing of polished concrete, marble, newer epoxy painted flooring or any other sensitive flooring. Will not harm polished or painted flooring. Equivalent to Nylon, Nylex. Usually white or black in color. These can be made in a stiffer Nylon, if desired. Please call 800-277-3780 for details. 38"L x 9"OD. Fits Factory Cat 420-C and 430-C cylindrical scrub brush riding scrubbers. Some units (420, Disc) require two 22" disc brushes instead of cylinder brushes (use two 23-421N, .028" Nylon disc brush - 21" block diameter). Please check your unit before ordering. Two cylindrical brushes create a 42" wide scrubbing path. Two brushes required. Priced each. Replaces Factory Cat 40-521N. Our Part Number FC 40-521N