The ProLED Select T8 Linear Hybrid (Type A+B) lamps offers the most versatile installation solution for your linear fluorescent T8 or T12 retrofit needs. Fully certified as a UL 1598C retrofit kit in single end or double end ballast bypass scenarios (UL Type B) and UL Listed for use with electronic T8 fluorescent ballasts (UL Type A), these lamps provides the perfect, hassle free solution for whatever the project requires, when being used with an instant start, programmed start or emergency backup ballast, no fixture re-wiring is needed. If the ballast fails in the future, simply re-wire the fixture with 120-Volt to 277-Volt line voltage using either single end or double end wiring. This CCT selectable hybrid comes in 2 ft., 3 ft. and 4 ft. lengths and offers users the ability to select between 3500K, 4000K and 5000K kelvin temperatures by simply sliding the selector on the tube to the desired color.