SE GC120B Tube and Pipe Brush Cleaning Kit, 21-Piece 6 piece stainless steel brush sizes: 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm 6 piece nylon brush sizes: 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm 6 piece brass steel brush sizes: 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm Brush length: 4 inches For cleaning various surfaces