Citronella spray collars are devices designed to deter dogs from unwanted behaviors, such as barking. These collars release a burst of citronella spray, a natural repellent, when the dog barks. The scent is unpleasant to dogs, encouraging them to stop barking to avoid the spray. These collars are often considered a humane alternative to shock collars, as they do not cause pain or discomfort. They are adjustable and can be used for various dog sizes. However, effectiveness may vary depending on the individual dog's temperament and training needs.