All of the shanks are 3.2mm(1/8inch) and compatible with other multi-tool machines including .These 6PC HSS rotary burrs are perfect for all sorts off jobs like Model making and the like.Using an engraving machine or mini-Drill various forms of cutting part provide efficient processing which materials length is about 40mm.For processing of metallic and Non-metallic surfaces.Great for craft, airfix modelling, home, repairs etc you .Shank Diameter mandrels: 3.17mm(1/8inch).single one Length: 40mm.colour: SilverMaterial: High speed steelPackage Contents: 6 x HSS rotary burrOnly 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.