The mini No Bark Training Collar is a newly redesigned digital system with a microprocessor. It fits small to XXL size dogs. The more compact collar makes this unit very lightweight and comfortable for your dog to wear. This unit has a replaceable 6-volt battery system, which makes this collar very lightweight. You may use an alkaline or lithium battery for your convenience. This specially designed magnetic collar clip turns the unit on and off; no more losing magnets. The digital numeric display shows the 8 different intensity level adjustments. Data memory system saves last used intensity setting when unit is turned off. Comes with a built-in magnetic on/off switch. This bark trainer is the best choice for both very stubborn dogs and very meek dogs. Specially designed vibration sensor picks up vocal cord vibrations when the dog barks. This high quality sensor helps to eliminate unnecessary "shock" from outside vibration caused by trucks, other dogs barking, scratching and dog tags. Delivers 1/2 second corrective stimulation. Automatic three-second safety delay between stimulations gives your dog added protection. Waterproof. Battery included. 1-year warranty.