305mm scrub, Polypropylene block, filled very stiff Polyester. Hillbrush offers two 305mm heavy duty scrubbing brushes, the B759 and the B770. The polyester in the B759 is 0.75mm diameter and is 63mm out. In practice the B759 is better for larger areas where the surface is even and there are no dips for soil to hide in, where the larger filaments tend to skid over the top and don't reach it. Recommended handles ALH27, ALH7.