Feature:1. Real Time Calls: Two way voice intercom doorbell allows you to make real time voice calls with visitors. Highly restored sound allows you to identify the visitors outside the door based on voice.2. Loud Ringtone: The ringtone is 108 decibels, which is larger than the mobile phone ringtone, ensuring that you will not miss any visitors when you are busy.3. Long Standby Time: Doorbell external machine built in large capacity 1200 mah battery, if pressed 5 times a day, a call for 1 minute, can work normally for 6 months.4. No Drilling Installation: The outdoor unit is installed by pasting. The indoor unit is powered by plugging. The installation process takes only a few minutes.5. Comfortable Button: The doorbell button adopts plastic and silicone structure, high light uv process surface, which brings comfortable and smooth touch and press feel.Specification:Item Type: Wireless Intercom DoorbellMaterial: ASBSize: Approx. 14 x 7 x 3cm / 5.5 x 2.8 x 1.2in Battery Type: Polymer lithium battery (Shipped with built-in battery)Battery Model: 103040Battery Capacity: 1200mAh.Package List:1 x External Machine 1 x Internal Machine 1 x Screwdriver 2 x Wall Adhesive1 x Instructions