InterLux EXTREME HPS bulbs are designed specifically for indoor growing. They have a light spectrum shifted towards the red, and are used during the flowering stages of growth. Tested and developed to work perfectly with electronic ballasts, these bulbs have an extremely high lumen output and a wide color spectrum for maximum yield. Standard E39 Base. 1 year warranty against original manufacturer defects. Works with electronic ballasts only. 215,000 LUMENS