Makita 743209-A 2-3/4" Knot Cup Wire Brush Carbon Steel - 5/8"-11 Arbor Ideal for tight operations, corners and angle welds. Rugged knot construction. 0.020" Type 302 Stainless steel wire for brushing components. Highly corrison resistant eliminating the problem of contamination. Diameter: 2 3/4", Arbor: 5/8" x 11, Max. safe speed: 14000.