Useless unless your dog heels perfectly
If you dog pulls at all you will be sore by the end of the walk, and I would definitely not recommend using this every day if you're dog is not perfectly well trained to heel.
Was absolutely unsuitable for my puppy. When the dog pulls it narrows the elasticated belt and digs into your waist and back. Prolonged use caused back and kidney pain and my puppy is only a medium sized breed.
I think I nearly ruptured a kidney the time she jumped off a 10 foot embankment after some ducks while still attached to me, too!
If you want a hands free walking belt for an energetic dog, or a pup that is still in training, I would recommend one of the ones designed for use with huskies, canicross, skijoring etc as most of these offer sufficient support across the back so as not to cause you any pain.