The Arcadia LED T5 HO Lamps are direct replacements for 24W, 39W and 54W T5 HO lamps. With four different color temperatures to choose from, these lamps can support plants and corals just as well as T5 HO lamps. They'll fit right into your fixture with two pin connectors on each side, just like a T5 lamp. No extra ballast or connector to worry about. Because they only use 1/3 of the electricity of T5 lamps, they will pay for themselves within one year (even in areas with low electricity prices). The Arcadia lamps have a 2-year warranty and can last up to 5 years.