SmaInHand 720P HD Metal Outdoor WiFi Doorbell Video Door Phone with 8GB SD Card Inside, Full Duplex 2 Way Audio Same Time, 3 Walls WiFi Distance, Connect to Doorchime Technical Features - with 8GB Memory inside,720P 1 Megapixel 1080*720 H.264.3walls+30meters super long WiFi distance and Full Duplex 2 way audio same time. 10DB antenna, Night vision distance: Max.2 meters/ IR-CUT:Optional/ WiFi Antenna: 3DB/6DB/10DB/16DB Optional/ Size: L55W40H129mm/ Working Temperature: 2050/ Working humidity: 10%80% no condensation/ IP level: IP65/ Memory: 8GB Memory inside. Optional, Max. 32G. See and Speak with Visitors Using Your Smartphone, When Visitors Press the Doorbell, Doorbell Sounds and Meanwhile Camera will Start to Work, Sending Real-time Picture and Call to Smart Phone. It is easy and quick to install. The user manual is pretty clear and complete both in installation/setting up/operation Tamper Alarm, "sound-priority-technology". Not like thief can open WiFi doorbell to open your door, our WiFi door bell is with Tamper Alarm which if thief open devices screw, the built-in tamper alarm detector will be trigger and its built-in siren will have loud alarm skirl sound to scare away the thief and notice your neighbor and send alarm ring to max 5 smart phones to stop thief open door via open device.