TN 86021 43" 24 Single Row .065" Heavy Grit Abrasive Bristle Main Scrub Brush Set for Tennant 530E. Splined Drive. Includes One Large (24 SR) and One Small (8 DR) Main Brush per Set. Our most aggressive bristle designed for heavy duty scrubbing and stripping on unsealed or sealed flooring with heavy soils. Priced per set of two brushes. One set required for brush changeout. Replaces Tennant 86021. Our Part Number TN 86021