Be sure your fixture can accommodate the large ballast size of these lamps. And also be aware they may take up to five minutes to completely warm up to come to full intensity. I'm told that these lamps should be used in all your lighting for the shoot rather than mix different type lamps for better consistency of color temperature. However, I've used these lamps in fixtures for key and fill in Westcott TD6 instruments with soft boxes for interview shoots, then used an Arri 300 for a back light with no discernible problems. The idea was to use as many cool lights as possible, yet retain as much intensity as possible without gelling fixtures and losing intensity to match the color temperature of all the lights. I chose tungsten-temperature all around because I wanted that beautiful light that the Arris produce and still keep the set safer and the talent cooler in the process. Since I couldn't control a CFL fixture for the back light like I could an Arri, and I didn't want to blue up an Arri and lose the intensity, the tungsten-temperature CFLs was my solution. In film school, we were taught to use the terms "lamps" or "globes" when referring to these items, not "light bulbs." Just a snob thing I suppose with film school terms. B & H has hardly any lamps listed on their site using the search term "light bulbs" unless you're looking for household items. Just saying...