Size detail: each of the grinding head is about 0.16 Inch/ 4 mm in diameter, 0.94 inch/ 24 mm in length, and the part measures about 0.12 inch/ 3 mm in diameter, length is approx.1.81 inch/ 46 mm. Solid material: burr grinding stone file is made of grinding stone with good hardness, suitable for metal polishing, especially for steel parts after heat treatment, durable and not easy to get broken. Applicable occasions: these polishing grinding are widely applied for machinery, bearing, mold, casting parts deep hole, different internal surface, welding spot, welding seam grinding and burr grinding. Package content: comes with 50 pieces burr grinding stone files, enough for you to apply in and meet your replacement needs. Material:Chrome steel jade + alloy colour:+silver Package Contents: 50 x Burr Grinding Stone File Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.