At the first spray, your dog's natural curiosity will be to seek the origin of the new odour. The dog will very quickly learn that when he or she barks, Aboistop Sprays! Through this harmless conditioned reflex, Aboistop discourages your dog from barking. In a few days, the dog learns to keep quiet while wearing the collar. With the deluxe Scentless (Citronella refill available) you get even more comfort, more control and more features.