Features： 1、18PCS IN 1 SET: Including 18pcs emery grinding heads, with 4.0mm 4.8mm 5.5mm size, sufficient quantity to meet more different grinding needs. 2、DURABLE MATERIAL: The emery particles are finely and uniformly polished, hard and wear resistant, the ti plated surface increases corrosion resistance. 3、EASY TO INSTALL: These grinding heads have 3mm diameter shank and can be mounted on electrical tools such as electric grinder, drill, etc. 4、APPLICABLE CHAIN: 4.0mm bit is suitable for chainsaw 3/8 chain, 4.8mm bit for 325 chain and large 3/8 chain, 5.5mm bit for large chain saw 404 chain. 5、MAIN PURPOSES: These grinding heads are commonly used for metal, chain and wood polishing and sanding etc, which are efficient and durable. Specification： Item Type: Grinding Burr Set Material: Emery Shank Diameter: Approx. 3mm / 0.12in Applicable Tools: Electric grinder, electric drill and other electric tools 4.0mm Grinding Head: Suitable for chainsaw, for 3/8 chain 4.8mm Grinding Head: Suitable for small chainsaw, for 325 chain, large 3/8 chain 5.5mm Grinding Head: Suitable for large chainsaw, for 404 chain Package List： 18 x Grinding Head