Wireless Watch Calling System RF Wireless Technology Rechargeable Battery Waterproof Nurse Calling System with 3 Prompt Mode Item Type: Wireless Watch Calling System Material: ABS Operating Frequency 433.92MHz Charging Voltage: DC5V Battery Type: 602030 Built in Lithium Battery Capacity: 300mAh (Ship with Inbuilt Battery) Working Current: 100±20mA (Vibration, Buzzer Mode), 75±10mA (Vibration Mode) Standby Current: 10±5mA Receive Sensitivity: -107±2dBm Decoding: Learning Code Waterproof Grade: IPX7 Working Temperature:-20℃ to 60℃ Button Launcher Parameter Description: Operating Frequency: 433.92MHz Battery Model: 12V23A (Included) Battery Capacity: 30mAh (Included) Emission Current: 10mA±3mA Standby Current: <1uA Open Distance: 100-200 Meters / 328-656ft Keystrokes: 1,000,000 Times Waterproof Grade: IPX7 Working Temperature:-20℃ to 60℃ Single Key: CALL