Not much to say here. I'm not a truck driver, but I do some volunteering. I need to do some basic troubleshooting (since I'm the tech nerd). I don't know much about trucks other than this does what it says. I had no issues with it.

It really works well

Effective at testing output from the tractor. Note this is designed for tractor trailers and not passenger truck 7-way pins as there are different pin styles and will not fit.

This is a nice, solid little product that is well designed as a diagnostic tool for checking circuits connecting truck and trailer. Each pin has a dedicated led to verify the circuit, and they are well marked as to function. Unfortunately, I mis-read the online description and this unit is NOT compatible with a 7-pin, flat-bladed connector such as those used for connecting a travel trailer to a towing vehicle, which was my intended purpose. This device is intended for Round pin connections, not Flat pin connections. So be certain this is what you want before ordering it.

This tester was easy to use, performed well, and detected my issue with my seven way pin quickly!