Effectively and humanely stop your dog from barking with the SportDOG Brand® NoBark 18. Patented Perfect Bark® sensor delivers a static stimulation via the contact points only if it detects BOTH vibration from the vocal cords AND the sound of the bark—for firm, fair and consistent correction. NoBark 18 provides 6 levels of correction in each of the low, medium, and high stim ranges, for a total of 18 levels. In each stim range, the correction starts at the lowest level and progresses to the next each time your dog barks within 30 seconds of the previous bark. If your dog doesn't bark again within 30 seconds, it resets itself to the lowest level of correction in that mode. As an added safety feature, the NoBark automatically shuts offs for 3 minutes if your dog barks 15 times or more within a 50-second period.