T8 fluorescent tubes. T8 tubes have a diameter of 25mm (or one inch) and are often used in ceiling fittings and some under-cabinet lighting. They have been the most common source of fluorescent lighting for many years.

They are available in a range of sizes and wattages and colour temperatures from warm white, to daylight white.
Unlike T4 and T5 tubes, the length of a T8 can usually be determined by it's wattage.