Used for repairing and cleaning damaged threads on oxygen sensor ports or spark plug threads

21mm hex bolt in the middle with retaining spring to fit 21mm deep socket

Rubber ring eliminates slip

Suitable for most cars

Not for use with impact driver

Three options:

• Double-ended for both 10mm and 12mm threads. 
• Double-ended for both 10mm and 14mm threads. 
• Double-ended for both 14mm and 18mm threads.