Did you - like me - a dog who runs spontaneously happy times with full force in the line, then you have to fight more times with shoulder pain. This is why I bought the shock absorber, and it really helps. However, my dog is with only 20 kg of body weight at the lower limit of the weight class, for this shock absorber has been made. The carbine is actually too heavy for him, and the shock absorber expands and only when force is applied properly. My conclusion: Prima suitable for dogs over 25 kg upwards, which tend to project quickly. For lighter dogs it no longer makes as much as it is better to resort to a lighter model.