Features: Easy to install and use. 2pcs AAA batteries, can work for about one year, low power. Including indoor part and outdoor part, keep online. Wifi RF transmission, super penetration, no need to worry about losing signal. 2 megapixels, 80 viewing angle, F2.8 large aperture. The picture is clear and undistorted. 30cm adhesive installation or screw fix installation. Anti-disassembly alarm: If the outdoor part is detached from the wall, the indoor part will ring. Mobile phone remote view: When someone presses the doorbell, the outdoor part will take photos automatically and send photos to your phone in real time. Photos of each visitor are stored on the server for later viewing. HD night vision, working for 24h.