1. PracticalMade from durable material, this grinding and polishing tool is practical to use and offers longlasting performance. 2. Knurled Nut Tension ControlEquipped with a fine stone and a knurled nut, this tool allows for precise tension control during operation, enhancing grinding and polishing results. 3. Flexible Shaft for Easy Use: Featuring a flexible shaft, this tool is easy to operate and provides automatic centering, making it convenient for grinding and polishing auto engine brake cylinders of various sizes. 4. Fast and VersatileWith a controlled spring and an extension control limiter, this tool enables quick and efficient transitions between cylinders, ensuring the fastest cutting speed. It is suitable for various vehicles, including cars, trucks, buses, tractors, industrial engines, and small aircooled engines.