Safety Angel Water Immersion and Anti Lost Double Protection Alarm One Bracelet unit is included in package. Safety Angel works as Anti-Lost Alarm, Safety Angel worka as Anti-Drowning Alarm. This small, easy to use device is used by the parent or guardian to detect the Bracelet wearer It is obvious that Safety Angel increases more security to your kids because of the added anti-lost alarm. Detecting range 30-40 meters, Safe material, No harmfull radiation