Feature 1DOORBELL UNIT: The pack includes 2 pcs of a doorbell system that can alternate between ringtone call and intercom mode. 2INTERCOM FUNCTION: The two units can be used as an intercom for two-way communication without raising voices at home. 3LONG RANGE: The voice intercom device can transmit up to 1000m in open areas and 20 to 50m through walls, making it highly practical. 4INDICATOR LIGHT: The voice intercom units are thoughtfully designed with indicator lights for intercom and power, allowing users to see clearly at a glance. 5LONG BATTERY LIFE: This two-way voice intercom features a built-in large capacity battery and utilizes an intelligent power-saving chip for an extended battery life. Item Type: 2WayVoiceIntercom Material: ABS Model: H8 Battery: Rechargeable Lithium Battery 3.7V 2000mAh (Built-in) Use: Suitable for household, office, laboratory, medical environments, etc. Basic Parameter: Working Temperature: -20 to 55 Transmission Distance: 1000m in open area, 20 to 50m through walls Operating Frequency: 410M to 490M Package List: 2 x 2 Way Voice Intercom 2 x Base 2 x USB Cable 1 x User Manual