Prime-Line Products U 11187 Prime-Line Products Digital Door Viewer, Black Digital 2.75 inch LCD screen, .3 Mega Pixel CMOS, 320 x 240 resolution Fits 1-3/8inch to 3-1/2 inch thick doors, 9/16 inch diameter hole Uses 2 AAA batteries, good for over 700 views, included in package 105 degrees of view Activates with push of a button on inside case As with a traditional door viewer, quality of view depends on available light outside the door. This door viewer must have exterior lighting available at night in order to provide a properly exposed image on the viewing screen.