Sylvania T8 tubes are fluorescent tubes with a G13 base. This base has two pins that are 13mm apart. The diameter is 26 mm. As usual with fluorescent tubes, the length and wattage are related. So when picking a new Sylvania T8 tube, make sure to choose the right specifications. You can use the filters on the left to select the perfect fluorescent tube for your application. Did you know that Sylvania also produces LED tubes? These fit your fixture perfectly but use less energy.