Tool question

[whiskeyding]

Cleaning our shop at work and found this. I have a plug and need a bigger one. But don't know what it's called to Google it. Says Apex 190-5

Sent from my E6810 using The Garage Journal mobile app

 

[Old Man Roger]

I wanna say I've seen that shape on deck screws?

 

[Caddybill]

 

[ttpete]

It's for clutch head screws. GM used them years ago.