Hot Spot&reg; Basic Automatic No Bark Dog Training Shock and Bark Collar Control With 7 levels of Correction Bark-control collar sends harmless static shock to the dog whenever it barks Adjustable nylon collar senses vibration in dog's throat during barking 7 sensitivity levels (1-7) adjustable for the different size of dogs barking Replaceable 6-volt Battery and Low battery consumption Generally recommend for 18-120lbs dogs.