4-in-1 security door viewer built-in digital camera, color display, intercom & chimes 2.4 in (6 cm) TFT color screen,Auto/Manual picture, stores up to 100 pictures taking function,Built-in memory operates on 4 x AA alkaline batteries with run time of more than 1 year so simple to use that even senior citizens and kids can operate! the visitor’s picture can be taken even in poor light conditions