The VBC-10 Vibration Bark Control Collar offers 10 combinations of vibration stimulation. When the dog barks, vibration is delivered from one of the two vibration points. The duration of the vibration is random, which interrupts the dogs bark. The Perfect Bark sound & vibration sensors ensure that only your dog's bark causes correction. The waterproof collar adjusts to fit neck sizes up to 27 inches and features an automatic safety shut-off.