16MM - 3/8" Drive - 6 Point

 Fits what most Americans (including ourselves)

call a 5/8" Spark Plug.  If you were to measure a 5/8 NGK or Bosch

plug, you will find it is actually a 16mm. Either way, a 16mm socket and

a 5/8" socket only have a .0050" (5/1000's - five thousands of an inch) difference.

16mm = .629921"   /   5/8" = .62500   /   Difference = .0049" (4.9/1000")

You Will Receive One (1) Socket