I have one and it's OK for a ballpark figure. I think it's more accurate if you've driven a short distance. After I jumped up and down on the coupler a few times I got an extra 100 pounds of tongue weight, which is where the weight stayed after driving. I just carry the box it came in with me, so I always have the other ball. It does not come with a 1 7/8 ball, so if you need one, it's extra.
2019 Silverado LTZ 1500 6.2L 3.42 Max Trailering Package
2018 Freedom Express 192RBS
2016 Silverado LTZ 1500 5.3L 3.42
2015 Jeep Wrangler Rubicon 3.6L 4.10
2020 KZ 130RBSE