Expert Quality, spark plug chaser, which covers two common sizes, 10mm and 12mm spark plugs threads. Able of fulfilling two purposes on motor vehicles, firstly, it cleans spark plug threads in the head, by getting rid of excess grunge, dirt and other particles that become embedded in the thread. This action results in a longer thread life and more efficient operation of the spark plugs. Secondly, it’s used to restore damaged threads, which has the potential to cause cross threading possibly making the spark plugs immovable. For these reasons, this spark plug chaser is a handy tool to have in any professional mechanics or vehicle technician’s toolbox.