beyond the length u201c l u201d of the filaments of the brush when stored within the jacket as this could permit the filaments to become disfigured by protruding outside of the openings 36 or 38 productivity guide and wear bars 27 and 29 are provided openings 36 and 38 extend lengthwise from each the respective upper ends 22 and 24 into the lower ends 26 and 28 respectively terminating at a predetermined distance from a lower end edge 40 and 42 respectively and are defined by top edge 60 and 62 bottom edge 64 and 66 respectively and side edges 68 and 70 respectively productivity guide and wear bars 27 and 29 extend across the respective panels 18 and 20 transversely through the panel openings 36 and 38 respectively and interconnect the side edges to retain filaments of the brush and serves as a visual productivity guide and wear indicator for filament length as well as lend rigidity and strength to the cover 10 the productivity guide and wear bars 27 and 29 aid in retaining the filaments 13 of the brush 14 the productivity guide and wear bars 27 and 29 can preferably include a curved rib cross section which aid in guiding the filaments 13 broken and unbroken into the jacket.