Features: 1. Full duplex intercom, talk like making a phone call 2. Automatic answering. The receiver does not require any operation and can directly communicate with each other 3. One click conversation, press the intercom button and speak directly, the other party can hear 4. Two way ringtone call, ring the ringtone 5. The actual distance of the open call is 500 meters, Floors 1 to 8 6. The appearance is slim with a thickness of only 18mm, providing a tactile sensation when held in the hand 7. Battery 1800mAh polymer lithium battery, working normally 5 times a day for 30 seconds each time, for about 30 days, 8. The buttons are made of plastic and silicone structure, with high gloss UV technology on the surface, it uses all rubber buttons. 9 intelligent and user-friendly design, with intercom lights and battery indicator display. 10. When in standby mode, place it on the charging dock for intelligent charging and never power off Product Parameters: Battery capacity: 1000mAh lithium battery Charging voltage: DC5V Working temperature: -20 ° C to 55 ° C Transmission distance: about 500 meters in open space, 20-100 meters in partition walls, floors 1-8 Operating frequency: 430MHz -490MHz Working hours: Fully charged and used for about 30 days Charging time: Approximately 5 hours to fully charge Music ringtones: 3 ringtones Ringtone volume: 5-level adjustment of size (with voice prompts) Product size: 116 * 56 * 18mm Charging dock size: 70 * 56 * 29mm