The Bellman & Symfon Visit Cell Phone Sensor is used with the Bellman & Symfon Visit Telephone/Multipurpose Transmitter to let you know when your cell phone or tablet screen lights up for example when you receive an incoming call or message from Facebook Twitter and other social media sites. Place the Sensor on top of the mobile device and connect it to the Visit system to be alerted with sound flashes or vibrations when someone is trying to reach you. The Visit Cell Phone Sensor may also be used with Bellman & Symfon Alarm Clock Pro or Alarm Clock Visit vibrating alarm clocks for cell phone ring notification.NOTE: The Visit Cell Phone Sensor must be used with the Visit Telephone/Multipurpose Transmitter for proper operation.Features: Activates Telephone/Multipurpose Transmitter which in turn signals a Bellman & Symfon Visit receiver. May be used with Bellman & Symfon Alarm Clock Pro or Alarm Clock Visit for cell phone alerting via these 2 clocks. Activated when display lights up on smartphone or mobile tablet. Uses one AAA battery (included). Dimensions: 0.9 in. Diameter; 1.3 in. H (24mm diameter; 34mm H). Item Weight - 1 lbs.Includes: Visit Cell Phone Sensor. 3.5mm cord with battery pack. One AAA battery. User manual. - SKU: HRSC2378