Lessmann LES456278 Knot End Brush with Shank 29mm x 0.35 Steel Wire The Lessmann Knot End Brushes are fitted with a 6mm shank. When the brush is in rotation it will open up and increase in diameter. This enables the operator to work in hard to reach areas such as drilled holes and recesses of all kinds. The Lessmann Knot End Brush With Shank has the following specification: Diameter: 29mm. Wire: 0.35 Steel.