Lessmann LES482214 Knot Cup Brush 65mm M10x2.0 0.50 Steel Wire Knot Cup Brushes are for heavy-duty use for the preparing of metal surfaces before painting and the removal of slag rust scale or concrete waste. Lessmann knotted brushes are filled with a special steel wire of high tensile strength in order to meet the demands of this type of brush. Products marked with a * have a bridle fitted which an be removed to expose a further 20mm of useable wire. Diameter. 65mm. Bore. M10. Wire Gauge. 0.50. Wire Type. Steel. Max. R.P.M. 12,500.