I have the original Hitch Haul that CURT bought out. Works alright but display is an analog dial vice digital so the tolerances are also affected by your reading of the dial. Pretty much plug and play with the downloaded app for newer vehicles if it is in the library, just enter the VIN. There is also a manual calibration involving stop and go driving and manually entering vehicle weight and your weight for the tongue weighing calibration. I bought it when my TV was a 2008 Ford Explorer and that was not in the library. You have to find a level, straight, empty road to do your start stop calibrations. Between Measurement runs you can change directions.