Been looking at these, anyone used one? Or anything similar?

Sitting on the fence re.magnets really, but having never used them I can't really have an opinion. I'm guessing its just to buy one and see if it works!

Its for my lovely ginger dog, she is 11 and just been slowing down the last year or so, doesn't seem arthritic or anything, just understandably slowing down and wondering if it would help. Will probably give one a go anyway and hope for the best!