I let a contractor friend borrow my 5 hp CH compressor, he had it for a while and when I got it back I found he had removed the part that I believe is the regulator though I could be mistaken. It's missing the part with the knob that would let you set the minimum air level, so now I have to run over and turn it off and on manually trying to maintain a usable pressure level for my little cup sprayer. I have seen Harbor Freight sells a regulator with adjustment knob but am not sure how to attach it.