This 4″ Adjustable Cylinder Hone Tool is designed for restoring and smoothing the inner walls of engine cylinders and brake caliper cylinders. With an adjustable range of 2″–7″ (50–177.8mm), it fits a wide variety of automotive, motorcycle, and small engine applications. Equipped with three durable 220-grit stones, it efficiently removes carbon deposits, rust, glaze, and minor surface defects to help restore proper piston movement and improve engine performance. The flexible shaft and self-centering design ensure stable contact with the cylinder wall for consistent honing results. Simply attach the tool to a low-speed electric drill, apply lubricant, and move it up and down inside the cylinder bore for smooth and effective cylinder honing.