Item dimensions L x W x H 9.5 x 8.8 x 7.7 centimeters Number of batteries 1 AA -not included Voltage 12 Volts About this item PAGER HELP: Ideal as an alarm for those who need help quickly, such as the elderly, children, the disabled, pregnant women or the sick. Simply press the call button for timely and considerate care without yelling. It can also be used as a doorbell EMERGENCY ALERT: We can put it in our pocket or use the necklace (included) to hang it on our neck as a pendant. We can also attach it to the bed or the toilet with double-sided tape so that our parents or children can send signals in time WATERPROOF SOS TRANSMITTER: The call button is waterproof. Acceptable for bed/toilet solidsAcceptable for meal/soup splashes. And have it installed in the toilet, applicable in the following places: home, nursing home, clinic, hospital, etc. EASY SETUP: This caregiver pager system supports pairing between multiple receivers and transmitters. We can adjust the kits according to our needs.