Description Steel, Brass, Nylon Bore/Tube Brushes 8mm through 19mm (36pcs total) 1/4" Hex Shank for quick attachments and standard drivers. Twisted Wires for increased cleaning function and lower speeds Packaged in Blow Molded Case with extra storage compartments Clean Bolts, Ports, Holes, Guides, Tubes, misc parts, rims, bushings, slides and MANY more! Recommended operation speed (900rpm or less) 1/4? Driver handle with quick lock adapter