Forney Power Tube Brush, 3/4 in. Stainless steel power tube brush with 1/4 in. (6.35mm) shank. Use for swift and easy cleaning of plumbing joints prior to soldering. Simply insert brush into a power drill. Stainless steelSimply insert the brush into a power drill.1/4 in. shank.Use for swift and easy cleaning of plumbing joints prior to soldering.