EYE Metal Halide conversion bulbs operate on High Pressure Sodium grow lights to create a complete growing system with a simple bulb change. Higher lumens and 4500° Kelvin compared to 4000° Kelvin for competitve lamps. Metal Halide conversion bulbs operate on wattage specific HPS lights (ballasts) and are used during the vegetative growth stages with a simple bulb change. These products have the same specifications as the Eye Hortilux Metal Halide conversion lamps.