Replaces 22' 24W T5 HO lamps. Fits into fixtures just like a T5 HO bulb. Lower power consumption. Only uses 8 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. Actinic color temperature for reef aquariums. Reduced heat. Much less heat than T5 HO lamps. 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.