I have purchased (2) JSP-012 gauges. I compared the horsepower and pressure readings between two Jaco gauges and my two boost gauges: the two Jaco gauges show the same pressure at both low (8psi) and high (60psi) and tested them on different guns on mine Property. Port cargo pressure readings did not agree with Jaco's gauges or with each other, especially one day when I checked the pressure at 34 degrees Fahrenheit. Now let's talk about airflow. Jaco is very impressive both when filling and using the deflation button. Where Harbor Freight gauges are very limited when inflated and even worse when deflated (on those with a deflator knob). Jaco's new automatic chuck adapter is impressive. Easy to use and hasn't leaked yet. I will inform you if this changes. Finally, at my age (retired), I can't stress enough how easy it is to read sensors without having to fumble for my reading glasses. Even with reading glasses, I find the port display very difficult to read.