FC 32-521C 32" 18 Single Row .035"/180 Mid Grit Abrasive Cylinder Scrub Brush for Factory Cat / Tomcat 34 (3400, Magnum 34, GTX 34) 35, 35SS, 38, 40, 40HD and 350 Scrubbers with Serial Numbers Below 50000 which require two 32" cylinder scrub brushes with older slotted drive hubs. A middle grit scrub brush for general duty scrubbing tasks. Narrow .035" diamater Tynex-A or Hahls Nylon filament impregnated with 180 grit silicon carbide granules for reaching small cracks and into grout lines. Equivalent to Midi-Grit. Usually blue or grey in color. Fits Factory Cat and Tomcat 34, 3400, Magnum 34, GTX 34, 35, 35SS, 38, 40, 40HD and 350C scrubbers which require two 32" cylindrical scrub brushes (Listed as a 34" - 34" scrub path with brush overlap. 350C listed as 32" scrub path). These are the OLD style scrub brushes with the slotted drive system (newer style is a "star" drive with six notches). These are for units with serial numbers BELOW 50000. Please check your unit before ordering. For newer "star" style hub brushes, use 325-521C. Two brushes required per unit. Priced each. Replaces Factory Cat / Tomcat 32-521C