This Arcadia T5 HO LED Replacement Lamp 34" (for 36" Fixtures) 39W (equivalent) Tropical Pro is a direct replacement for 39W, 36" T5 HO lamps for 36" T5 HO Fixtures. It'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. This lamp only uses 12 watts of electricity, but the output is the same as a new 39 watt T5 HO lamp. Over time it will be comparatively brighter because it will not lose intensity like a T5 lamp. It will also not shift spectrum. Even in areas with low electricity costs this lamp will pay for itself in just one year. That is, if you compare the cost of a typical T5 HO lamp plus one years' electricity cost to the cost of this lamp and one year of electricity, it will be the same. However, you will not need to replace this lamp after one year. It's warrantied for 2-years and the expected life is 5-years. The Tropical Pro lamp accentuates reds and blues, and is appropriate for freshwater fish-only and planted tanks. Use in conjunction with the Freshwater Pro lamps. Features: Replaces 34" 39W T5 HO lamps Lower power consumption. Only uses 12 watts. Due to electricity cost savings the lamp will pay for itself in one year (factoring in the comparative cost of a T5 HO lamp) Pleasant shimmer effect Reduced heat. Much less heat than T5 HO lamps. Fits into fixtures just like a T5 HO bulb Reddish color temperature for freshwater aquariums 2-year warranty We do not recommend using this LED Lamp in a fixture with metal halide bulbs. The heat from the metal halide bulbs could melt the Arcadia LED Lamp housing causing the lamp to fail.