Suitable size: shafts contain the sizes of 7 mm (0.28 inch), 8 mm (0.32 inch), 9.5 mm (3/8 inch), 10 mm (0.39 inch) in diameter; The cutting head measures about 19 mm (3/4 inch) in external diameter and 6 mm (0.24 inch) in inner diameter, and the "O" style sleeve adapter fits pilot shaft over 7 mm to keep it in the center position Quality material: the cutter shafts are made of High-quality materials, which are rust-resistant, sturdy, with nice cutting strength for maximum drilling, and the sleeve adapter is made of High-quality materials; The pen trimmer kit provides a practical and convenient tool for your pen blank preparation process Easy to clean: the cutting shafts can easily clean and remove the extra glue, bits of wood, impurities, etc. from the tubes and make the tube cut flatter; Please make sure the cutting shafts mount into a drilling or lathe chuck correctly Various occasions: shafts are suitable for mounting into a drill chuck, lathe chuck, drill or hand drill, and they