These bulbs are made by Sylvania but one bulb burned out in a few days and they are not used all the time. I replaced it with a second bulb and it didn't work. I thought it might be an outlet problem because I just replaced the outlet assembly in my Broan range hood. I screwed a standard socket bulb into the lamp and it just died. Then I took out the last bulb in the 4 pack and it lit up as soon as it was screwed in. Apparently I paid for 4 bulbs and got 2 that work. I think I will buy these bulbs from a big store in the future.