Being an Odyssea dealer.... The bulbs are 150 Watt HQI. I know this post is old but I just thought I would clear up the question. I have no idea why they put 175 on the box and equipment. But, I had to purchase a replacement bulb and the distributor said there is no such thing as a 175W HQI and the bulbs in there Metal Halide fixtures are 150W. Maybe the ballast are 175W so that the bulb is not under powered?? But I know for sure that the bulbs are 150W.