Most thread restorers require separate inserts to match the specific threads of a damaged bolt. This one doesn't. The patented yet simple design allows the hardened steel cutters to adjust to any size, pitch or direction of thread — Imperial or metric from 5/32" to 1/2" (4mm to 13mm).
Attached behind the damaged area, the tool is rotated along the length of the threads from the inside out, cleaning unwanted deposits (accumulated dirt, rust, paint, etc.) at the same time as it reshapes any damaged portions.
Great for repairing fixed bolts on bikes, machinery, automobiles, etc. A highly useful tool.