Wireless Pager System 4 Watch Receiver 1 Call Button Waterproof Wireless Calling System for Home Factory Hospital Item Type: Wireless Pager System Material: ABS Watch Receiver Specifications: Working Frequency: 433.92MHz Charging Voltage: DC5V Battery Type: Lithium Battery Battery Capacity of Single Watch Receiver: 300mAh (Included) Working Current: 100±20mA (Vibration and Buzzer Mode), 75±10mA (Vibration Mode) Standby Current: 10±5mA Receiving Sensitivity: -107±2dBm Decoding: Learning Code Waterproof Grade: IPX7 Working Temperature: -20℃ to 60℃ Button Transmitter Specifications: Working Frequency: 433.92MHz Battery Type: CR2032 x 2 Battery Capacity: 240mAh (Included) Transmitting Current: 10mA±3mA Standby Current: <1uA Open Distance: More Than 100m/328ft Button Life: 1 Million Times Waterproof Grade: IPX4 Working Temperature: -20℃ to 55℃ Single Button: CALL