Tufted with polypropylene (.40" diameter) and durable 6/12 nylon (.016" diameter). Designed to clean deep grout lines and uneven floor surfaces. Dual filament construction combined to create a superior scrubbing action for deep cleaning. Flared tufting for edge-to-edge and corner-to-corner cleaning. Driver block is not required allowing for simple and quick change out time. Universal design fits all oscillating floor machines: stick, walk behind, and riders.