I just bought a new 80 gal,5 hp compressor and was under the impression it was a two/stage.Now I'm not sure.How is the best way to identify one?

A two stage has two cylinders, one larger than the other. It compresses first in the large one then again in the smaller one before entering the storage tank. Bob

Thanks alot for the reply. That is what I needed to know.

Also 99% of the time. you can visually follow and see. Air intake tubed into the 1st cylinder, exhaust from fist cylinder piped into the 2nd cylinder.. then exhausted into the TANK..

GL hope ya got your Two Stage..