This thing stopped working after 4 uses even with fresh batteries.. It seems to hum along okay although I didn't notice much relief from my knee pain. I still think these things can work, so I'll order a different one, but this one is for the dogs. Well, no, don't use it on your dog.

It does what you want it to. Excellent addition to your RV whether or not you have a leveling system installed. Just being able to check a site for level before committing to it is worth the price.