KD Tools 3689 Back-Tap 12-Millimeter Reverse Spark Plug Re-Thread Tool

KDT3689 Features: -Uses light grease on the end to trap filings and keeps tool easy to use.-Threads at the base of the port.-Reduces dirt and metal from being driven into the cylinder headThis is a handy and easy to use thread chaser.  It not only cleans and rethreads sparkplug ports, but it uses the good threads at the base of the port.  It reduces dirt and metal from being driven into the cylinder head..-12mm Spark Plug Re-Thread Tool. Warranty: -Lifetime warranty does not cover abuse.