Tested, cleaned and retested 4 sets of injectors I had as soon as they arrived and am impressed with how well they work. Found a dead injector and several in dire need of cleaning. This tool will be a great addition to my shop. He's had trouble checking flow on a set of old low impedance injectors, he can't really. It just shuts down instantly, which is good news because that means it has internal overcurrent protection so it doesn't damage the injectors. I'm still not sure what the graduations on the glass cylinders mean and could use a side feed adapter.