Fluorescent lighting is the most common type of lighting found in commercial and industrial applications throughout the world. The fluorescent lamp is easily adapted in diameter, length, wattage and color to suit a variety of uses. All fluorescent tubes are arc source lamps meaning that they rely on a ballast to convert input voltage into the correct operating current for a particular lamp type. This means that all replacement fluorescent lamps must correspond to the ballast with respect to the correct wattage, number of lamps and diameter of lamp. Tube diameter is a significant parameter for proper lamp and ballast function as many fluorescent lamps are the same overall length but with different diameters. This is key because the T5 (5/8" diameter), T8 (1" diameter) and T12 (1.5" diameter) fluorescent lamps all operate at different amperages. Fluorescent lamp length is another important part of lamp identification since all fluorescent lamp length measurements are nominal and are measured from the back of one socket to the back of the opposing socket. Please contact your Kelsun sales representative if you require additional assistance with proper identification of fluorescent lamps or if you wish to learn about fluorescent color options for your existing lighting systems.