My dogs had already been through 5 citronella spray collars which worked fine by the way but arent that robust and 50kg of rottweiler doesnt take long to break them and i was beginning to lose hope

Within 4 hours the minute one started to even growl the other one was anticipating the ultrasonic noise and running upstairsthe other one is now reacting 2 days later but then hes older and more stubborn and takes longer to learn his lessons