The Wonderleash by Wacky Walk was invented to help dogs stop pulling on the leash.
The natural rubber leashes are stretchy and automatically pull the dog back through the bungee, so the dog is always pulled backward when it tries to pull on the leash. Furthermore, it's more comfortable to lead a pulling dog with the bungee, as the strain on the arm is reduced. For situations where the dog shouldn't stretch the bungee, the fixed part at the front of the carabiner is provided. You can reach in there to better control the dog.
Wonder Leash by Wacky Walk - Stretchable Dog Leash
The leashes come in 4 sizes, which are recommended depending on the weight class:
Size S: up to 9 kilos
Size M: up to 10 to 27 kilos
Size L: 28 to 70 kilos
The thicker the leash, the stronger the bungee. Of course, it's possible to lead a 25 kg dog with an L leash, because then the pullback is simply stronger.
It is recommended to use the miracle leashes on the chest harness.
Attention: The miracle leashes do not replace leash training!