Today i picked out a no. 80546 from advance auto (parts) it is a 5/8" with integral swivel, grips plug snugly, protrudes out the opening about an inch, where you attach a 3/8" extension, universal, etc. Fits that well perfectly. I really like the permanently attached swivel that will not pull apart.

PS the plugs in my car are recent and by Denso (platinum), so they are staying put. I had some fun today, and now i know.

 

Picked up a ratchet like breaker bar with a mechanism that reverses directions, for the serpentine belt, is also a handy tool you'll seldom use.