**600W BLUE is a metal halide lamp designed to operate on 600W electronic ballasts or core and coil (magnetic) HPS ballasts rated ANSI S106. All 600 Watt Core and coil (magnetic) ballasts are HPS rated, therefore, our 600W BLUE is a conversion lamp on this system. BLUE all the way through- start to finish: This lamp can be used as a standalone light source which will grow the highest quality natural looking plants throughout all phases of their growth cycles. Start with BLUE, finish with SUPER HPS: Growers who prefer to use metal halide for early plant development and then switch to high pressure sodium for flowering and fruit production can also successfully us this product. 600W BLUE allows aggressive vegetative growth using your existing HPS system. Simply switch back to your 600W HPS lamp for flowering and fruit production. Mix BLUE with SUPER HPS start to finish: Multi-light systems can combine our HORTILUXâ„¢ BLUE along with HORTILUXâ„¢ Super HPS lamps for a more balanced spectrum to produce higher yields and quality of plant growth throughout all phases of plant growth.