Wireless Intercom – 1 outdoor doorbell can be paired with 1 indoor doorbell, the perfect combination allows you to communicate with visitors at your door. Two-way Intercom – When someone presses the call button on the outdoor unit, the internal buzzer rings immediately to remind you. You can press the answer button to talk to someone outside. Clear Voice – Built-in high-sensitivity microphone and speaker, the 2.4 GHz signal provides clear and fluent audio effect during communication. Effective transmission distance up to 300 meters. Easy to Use – Ultra mini size ensures perfect portability and easy installation, small and beautiful, easy to install. Suitable for home, factory, hotel, hospital, supermarket and office. Product transmission distance: 200 meters in open space; 5-50 meters if there are obstacles. Feature: 1. The frequency of use of this product complies with national regulations and will not produce harmful electromagnetic interference. It can be used universally. This device complies with FCC, CE and CCC rules and regulations. 2. The outdoor unit is easy to install and remove the battery, with 4 AA batteries (batteries not included), and the indoor unit uses a rechargeable lithium battery. The outdoor doorbell is powered by 4 alkaline batteries for easy battery replacement. 3. The outdoor unit has a long service life, and 4 batteries can be used for more than six months. Low power consumption, the outdoor doorbell's standby time is up to six months. 4. Speaker sound, adjustable volume, changeable ringtone, clear intercom sound quality, can be used for mobile intercom. The speaker is adjustable, the sound is clear, and it can be used as a mobile walkie-talkie. 5. Long working distance, the maximum opening distance is 200 meters. Ultra-long wireless range up to 200M. 6. Easy to install, directly attached to the wall with 3M adhesive. Easy wall mounting with 3M tape. 7. Through code-to-code learning, one outdoor unit supports N indoor units without interfering with each other and without changing the code. By learning the code, the outdoor doorbell can be paired with the indoor doorbell. An external doorbell can be paired with N internal doorbells without interfering with each other. 8. Exquisite and small, beautiful and generous. Size: 100*60*14.8mm. Note: All data are manual measurements, please allow 1-3 cm error, due to the difference in light and display, there will be a certain color difference, depending on the physical object received. Delivery quantity: (according to the main picture)