Nylon Filament Brush 5" Cup Brush 5/8" 11 Thread (6500) Rpm. This unique nylon filament cup brush is made of a special nylon filament impregnated with silicon carbide. This nylon brush lasts up to six times longer than conventional wire brushes. Nylon filament cup brush uses include frame and body cleaning, polishing, deburring, scrubbing and brightening, surface refining and decorative finishing. Safe for use on metal, wood, aluminum, and plastic surfaces. This nylon filament cup brush is a must have for prepping truck beds before using any type of roll-on or spray-in bed liner material or for sound deadening. This will cut your prep time in less than half.