Found under the following brands:
Annovi Reverberi-AR, Westward, Bostitch, Black & Decker, Craftsman, Devilbiss Air Power, DeWalt, Emglo, Excell, Porter Cable, Speedaire
If your pressure switch is leaking out of the small bleeder valve on the side or if located underneath, order a tank check valve instead, your pressure switch is ok.
Wheeled Portable Single-Stage Oil-Bath Air Compressor Parts
Portable Single-Stage Oil-Bath Air Compressor Parts