I'm just reaffirming what waterppk said. This is absolutely worthless. It leaked from numerous places, and was unfixable. Terrible, simply awful. And not a true regulator, at least not how I'd think of one. A regulator limits the amount of air that goes to the tool at a set level. None of this initial surge at full pressure. To be avoided. They should pay to have people take these off their hands. This is the kind of thing that gives Harbor Freight its undeserved bad reputation.

The one I bought leaks at all of the fittings, couldn't tighten it enough to get it to stop even after wrapping it in teflon tape. Additionally the input/output sizes are specifically spec'd to fix the HVLP connection hose, they aren't NPT size. Finally, this regulator only works with a continually flowing air tool, like a spray gun, otherwise it just pressurizes to the maximum pressure on either side of the regulator over time.