EYE High Pressure Sodium conversion bulbs operate on a Metal Halide grow light and produce 25% higher blue and violet spectral energy than standard HPS bulbs. Use Metal Halide during the vegetative growth stages and the HPS conversion bulb during the flowering and fruiting stages for optimum growth. Create a total lighting system with a simple bulb change. These products have the same exact specifications as the Eye Hortilux HPS conversion bulbs.