The door stopwatch is also a portable alarm that gives a 120db beep when turned on, helps alert homeowners or renters if there is a burglar, and the neighbors and the security authorities may also.Easy installation - no wiring required; Battery powered (requires 1x9V battery, not included); Place it under the door, the gap between the bottom of the door and the floor should be 10mm (0.38in) to 35mm (1.35in), on a smooth floor you can try to use a type H sensitivity, vibration alarm.3 sensitivity levels - low - medium - high, with adjustable sensitivity switch on the side; The H level is the most sensitive level a vibrator can trigger an alarm; Notice when the alarm sound changes gradually, that means replacing the new battery.
