Wireless long-range intercom system with 3 adjustable volume levels and sound doorbell. 1. Long-distance intercom: The barrier-free long-distance call range supports approximately 1000 meters; no network or wiring is required, making it easy to use. 2. Long standby time: Built-in 2000mAh battery provides long battery life. Five 2-minute calls per day can last approximately 8 months, while the indoor unit can operate for approximately 1 week. 3. User-friendly design: Equipped with an intercom indicator light and power indicator, the user-friendly surface pattern facilitates quick communication. 4. Button design: The buttons feature a plastic and silicone structure with a high-gloss UV finish. At 18mm thick, they are comfortable and easy to grip. 5. Convenient: When the indoor unit rings, press the TALK button to communicate directly. Equipped with a charging cradle, it can be fully charged in five hours. Specification: Item Type: Wireless Intercom Ringtones Material: ABS Door Unit: 2000mAh 103450 Polymer Lithium Battery (built-in). Indoor Unit: 2000mAh 103450 Polymer Lithium Battery (built-in) Operating Temperature: -20-55°C Transmission Distance: Approx. 1000 meters without load Operating Frequency: B Speed ​​Frequency 462 MHz, A Speed ​​Frequency 434 MHz Charging Time: Approx. 5 hours for a full charge Music Ringtones: Optional Ringtone Volume: 3 adjustable levels (Sleep mode: volume button) Call Tone: 3 adjustable levels (Call volume button) Package List: 1 Transmitter 1 Receiver 1 x Charging Cradle 1 x Charging Cable 1 Screwdriver 1 User Manual 1 x double-sided adhesive strip, 1 x adapter cable