Function Description: 1.3.5 inch TFT LCD Screen 2.Peephole barrel (diameter) :14-22mm 3.Fits any door : 35-72 or 60-90mm ( thickness ),pls confirm the door thickness with dealer before purchase 4.Sensor : 1.3M pixels camera with zoom in and zoom out function 5.Screen will automaticly be in sleep model after 10seconds Once press monitor button 6.Monitor outside anytime when press monitor button 7.Used TF card as external memory,easily save pictures and videos to family computer 8.When visitor press Door bell button,machine automaticly turn on and take photo 9.Press UP/DOWN key to view photoes any time.Or Select preview mode in menu 10.3 pcs AA battery ,support to view outside for more than 1200 times