Fits door: 40-70,70-110mm (1.58"-4.32") Fits barrel hole: 14-25mm 3.5 inch: HD TFT LCD Sensor: 1.3Mega Pixel Viewing Angle: 165 Degrees(D) /120 (H) Power Source:4 AAA batteries (Usually more than 3 Years to change) Product Size: 128*72*16.8mm Color: silver, gold, champagne or customized 1. Back-light compensation technology,clear Image,vivid pictures 2. The Best Quality Peephole Camera in the market, same CVBS signal as Television in our home 3 Clear image even if against the sun. 4. More convenient for DIY installation, easier to replace batteries. 5. Press the button,display for 10 seconds, then automatically off. 6. Power saving design, one sets new batteries can be used more than 3 years for regular usuage