Kushina Black 4.3" TFT CCTV Tester for Security Surveillance Camera Video Analog Signal with Color LED LCD Monitor Wrist Strap This 4.3" security tester is designed for testing the surveillance camera. The security tester can be attached to the surveillance camera in site. It also has OSD menu and network cable testing capabilities. Additionally, it could be used as a power supply of 12V temporarily. The wrist strap design is humanized for convenient use. Audio and video input. Audio testing function, testing voice of the front end device is normal or not. If there is no video, it would turn to sleep mode after 3 minutes then you can switch in video to wake it up.