In order to install the Flyin' Miata NA and NB hood lift kit, you need to drill and tap one hole on each side. If you don't have a 6x1.0 tap, this is what you need. They're convenient to have around as half of the fasteners on the car seem to be 6x1.0.
Includes a 5mm drill bit and a 6x1.0 tap. These metric parts may be hard to find at your local hardware store.