Malish Clean-Grit 13 inch rotary scrub brush, built for wet scrubbing on narrow grout lines and uneven floor surfaces. Silicon carbide is impregnated through the nylon bristles, so the abrasive self-replenishes as the brush wears, and Malish rates it to outlast a standard floor pad by more than 100 to 1. The water and chemical resistant Tuff-Block base is built to last as long as the bristles. Fits L800P mounting blocks; 180 grit, blue nylon bristles, 0.035 in bristle diameter, 1.5 in trim length. Must be run wet.