Good quality but only good for small dogs, not medium

I really liked this in theory - the quality of the leash itself is good and being hands free/able to jog while walking the dog was very appealing. There are several caveats though - the magnetic hook isn't very strong when facing the strength of even a smaller breed of dog (such as a jack russel or other terrier) so a medium breed would very likely be able to break this without much effort. If you want to use this with a small breed then I would think it would be fine but use with caution in anything larger than a small terrier type.