The PetSafe Deluxe Little Dog Spray Bark Collar (PBC00-11283) is one of the smallest spray collars on the market, featuring a waterproof, lightweight design specifically suited for small dogs. Annoying or excessive barking activates the spray collar. A short burst of citronella is released to stop the dog's barking. Additionally, the PetSafe Deluxe Little Dog Citronella Spray Bark Collar ensures that only your dog wearing the collar can actually activate the spray collar - this is PetSafe's patented "Perfect Bark" technology.