Round Shank Size: 3/32inch (2.35mm) round shank size, suitable for most rotary tools Application: Widely applied to carving and grinding of various material such as metal, jewelry, wood, walnut and more; Highly recommended for olive core, beads, , wood, bone, precious soft metal and some other micro-inlaid items Material: High hardness, good toughness, high efficiency, fit for olive core, beads, , wood, bone, precious soft metal some other micro-inlaid items Different Head Sizes: Each Pack has 6 different shape of the sculpture to give you more flexibility for your engraving. Extra small sleeve needle diameter 1.0MM, small sleeve needle diameter 1.4MM, medium sleeve needle diameter 1.8MM, large sleeve needle diameter 2.3MM, overall needle length 44MM and Control: Engineered for smooth, accurate engraving, allowing for detailed designs and professional results in your crafting and DIY endeavors, Weight: 0.09259415004 Pounds, Manufacturer: BOFRHME