The 400W MH HIGH OUTPUT InterLux LIGHT BULB Makes your plants strong by giving them the right light for each growing stage. Metal Halide bulbs produce a blue spectrum light that best suited to the vegetative plant. The 400W MH HIGH OUTPUT InterLux LIGHT BULB Makes your plants strong by giving them the right light for each growing stage. Metal Halide bulbs produce a blue spectrum light that best suited to the vegetative stage of growth. This lamp has been tested and developed to work perfectly with electronic ballast, and features a high lumen output and a wide color spectrum for maximum yield. Standard E39 Base. 1 year warranty.