... 4.4-in-1 security door viewer 5.built-in digital camera, color display, intercom & chimes 6. Built-in memory, 2 ... :1.4-in-1 security video door phone2.built-in digital camera, color display, intercom & chimes3.User-friendly design4.so simple ... AA alkaline batteries with run time of more than 1 year Home Security 2.4" LCD Monitor digital door viewer with night vision