Review on NANPU 1/2" NPT Air Drying System - 5 Micron Particulate Filter, 0.01 Micron Coalescing Filter, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl W/Metal Gauge by Stephen Hobbs

I was really impressed with this unit. All the fittings I needed were included, plumber's tape (though it is really thin), and it came mostly assembled. The way they designed this makes each module interchangeable. I actually removed the module with the pressure gauge to do a pressure test, everything worked perfect without the filters attached. The included instructions are very brief and not translated well. Fortunately everything is marked with arrows for flow on the top of each module and the regulator has indications of how to lock as well increase/decrease pressure.The two reasons I marked this as 4 stars rather than 5: the filter drain valve assemblies and small air leaks.*For my small airbrush compressor, the drain valves do not close by themselves. I have to manually hold them shut in order for the filters to build pressure to hold them closed. Its a little annoying but still functional.*I'm also have issues with the fittings and modules holding pressure (compressor discharge is 57psi rated, gauge shows approximately that). With the supplied plumber's tape and the supplied fittings, I cannot hold pressure. I have a slow leak that short cycles my compressor. All the fittings are tightened except the pressure gauge which is very difficult to get a wrench on due to the small clearance between the gauge and the body. I have hand tightened it as far as I can.Recommendations to the manufacturer:*I would recommend either including a thin wrench that allows you to tighten the pressure gauge or install the gauge at the factory.*I would upgrade the plumber's tape to something a bit more robust. If it leaks at 60psi, I can imagine what others are experiencing.*Change the spring in the drain valves so low pressure/flow compressors can close the valves without manual interaction.