Review on Versatile Preciva Air Compressor Pressure Regulator with Dial Gauge and Four Way Valve for Enhanced Control and Performance by William Burnett

You need to buy the input and output connectors and a connector for the auxiliary connector. The plugs supplied are not US standard. I have other brands of air tools and these fittings don't work with any of them. It must be a foreign standard, but in the US they are useless. So you are basically buying a regulator body and a pressure gauge. You need to buy 3 more parts to use this. The threaded parts of the regulator body are 1/4” NPT.