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 solid carbon steel, which are rust-, sturdy, with nice cutting strength for maximum drilling, and the sleeve adapter is made of brass; 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 are helpful to polish the pen, mill the hole and clean the inner tube with the tiny size Offer convenience: shafts in different sizes fit your needs in your and wood working, which can increase the working efficiency and reduce the energy while doing drilling and milling. cutting head: The cutting head of the pen trimming set is solid and with pointed cutting, which is practical and can be applied multiple times without blunt. It is easy to polish the for flatness. Colour: Silver Material: Metal Package Contents: 4 x pilot cutter shafts in different sizes 1 x cutting head 1 x sleeve adapter 1 x hex key wrench Notes: Small parts are included, please keep away from children. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.