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. When used according to instruction, the Vibration Bark Control Collar safely reduces (and in most cases eliminates) nuisance barking. As a built-in safety feature, if your dog barks 15 times or more within a 1 minute 20 second period, the Bark Control Collar will automatically shut off for 1 minute. Waterproof adjustable nylon collar fits up to 71cm.