Imported from UK, quality seems good.  Cork-seal plunger function.  Not-so-common petcock thread used on vintage British motorcycles, 1/8 British Standard Pipe.  If in doubt, the hole in your tank is roughly 3/8" SAE.

Uses smaller ferrule and nut at line end, can be purchased here:  https://www.ebay.com/itm/182475906807

Seals at tank with teflon tape or fiber/statoseal washer, not supplied.   

I will answer questions promptly, good luck and thanks for looking.