Don't like headphones? Difficult to hear tones & whistles? Need to hear sounds around you while hunting? VIBRA-PHONETM 280 is was designed to solve these problems. Just clip it on to your detector and plug it into the headphone jack in place of your headphones. VIBRA-PHONETM 280 vibrates to indicate your target. VIBRA-PHONETM 280 uses a standard 9V battery. There are two adjustments. One sets the sensitivity or level when the unit will start vibrating. The other adjustment converts a short pulse of vibration to a longer pulse if needed. Set it once to match your detector. VIBRA-PHONETM 280 works with all common detector models.