Faithfull FAIWBS50 Wire Cup Brush 50mm x 6mm Shank 0.30mm This Faithfull crimped steel Wire Cup Brush is designed for light to medium-duty applications such as cleaning metal surfaces prior to welding or painting. The wire brush is fitted with a 6mm (1/4in) shank and is designed to operate with power tools with a maximum speed of 4500/min. Type: Cup. The FAIWBS50 Wire Cup Brush has the following specifications: Face Diameter: 50 mm. Shaft: 6 mm (1/4 inch). Wire: 0.3 mm crimped steel wire. Conforms to ISO 9001. and DIN EN1083-1 and 2.