Features and Benefits: Each brush has a 1/4 hex driver shank 1/4 driver handle with quick lock adapter 12 steel 12 Brass and 12 Nylon Brushes are made of stainless steel brass wires and nylon Included in a protective blow molded case 12 nylon 12 Stainless Steel and 12 Brass Bore/Tube brushes sizes 8 through 19 mm make up this kit. Also included is a 1/4 in. Driver handle packaged with the brushes inside the newly redesigned case.