There are three types of T8 LED tube lights. 1.Type A LED Tube – Plug and Play (Compatible with Ballast) Type A LED tube lights is compatible with ballast. It’s plug and play. However, product cost and maintain cost is higher. Ballast compatibility may be a problem too. 2.Type B LED Tube – Ballast Bypass Type B LED tube can install directly on T8 fluorescent light fixtures. However, ballast need to be removed before installation. There are two kinds of type B LED tube, which are single ended power and double ended power LED tube. Single ended power LED tube need rewire, but it’s cheaper. Double ended power LED tube can work directly on fluorescent light fixture after remove ballast. 3.Type C LED Tube – External driver Type C LED tube comes with external driver, which provides more flexible installation. However, product cost is much higher.