Awesome. I used this to regulate an 11-gallon auxiliary tank that is in-line between my 6-gallon 150 PSI pancake compressor and my tool(s). This makes it so that I can keep the compressor pumping 125 PSI into the tank (It's rated max), and then regulate the tank closer to the work area depending on the tool's needs. This cycles my electric compressor less often and keeps the noisy thing as far away as possible. I bought a second one to keep a separate regulated line in my garage so i can have 2 tools going at different pressures.
This just has 1/4" FIP (female) inlet and outlet, so brass connections can be purchased either from compressor accessories section or plumbing dept of your local home improvement store. Just make sure you locate the arrow on this unit and keep airflow going in that direction.
The knob seems fairly heavy-duty plastic, and the gauge seems accurate as well. I usually have my compressor alone set to around 90 PSI to drive 3" framing nails, and that's what this was set at as well when using the aux-tank. The body is solid metal. The gauge has a metal housing with a plastic lens. The gauge also has pipe-dope pre applied, so that is nice.
Yes, it comes with the gauge unattached, but if you have to twist the body on in a tight space, you will appreciate that.
EDITED: There IS an automatic bleeder valve that activates when you decrease the regulated pressure to the line. I didn't notice this at first because I fine-tune the knob with small adjustments. Making a bigger adjustment will release the pressure. If you are making smaller adjustments that don't activate the bleed valve, just use the tool a couple of times to get to the new pressure.
Overall, great value and quality feeling product. I recommend.