The AgroLED? iSunlight? VEG + UV T5 replacement LED lamps are designed for the vegetative period of your plants' life cycle, featuring 80% 5500ø K, 10% 460nm blue and 10% 380 nm UV. These iSunlight? T5 lamps are an intelligent LED that are specifically designed to work with your existing T5 fluorescent fixture. These LED T5 lamps are environmentally friendly and mercury-free. Not compatible with HF Agrobrite T5 fixture.