The components of a CCTV system are the video camera, the video monitor, and the coaxial cable which connects the camera and monitor. Camera selection will depend on available voltage, lighting conditions, and other environmental factors. Mounting should be on a vibration-free surface, as high as possible, with a protective cover, and without exposure to extreme heat or cold. Sunlight or other bright light should not directly enter the lens. When sufficient coverage is not given by a wide-angle lens, the camera can be mounted on an automatic scanning device. In selecting a monitor, consideration should be given to monitor size in accordance with viewing distance. Direct light should not hit the monitor. A video switcher allows the alternate viewing of a number of areas on a single monitor. The coaxial cable should be low-loss, high-quality RG-59/U. The camera lens and monitor screen should be periodically cleaned without solvents. The camera should be turned off when not in use. Make sure the CCTV contractor keeps spare components on hand as 'loaners' to reduce system down time due to repair.