These blue tint R7s are 240 volt.They would work in a 120 volt fixture, but would run at 50% output, which would defeat the purpose.If you tried to use these with a 240-120 volt step up/down transformer you would burn your house/studio down.The only way to use these bulbs is to buy a 240 volt fixture and use a step up/down transformer.This would not be practical if you live in the states, as you would pay out the arse for a transformer and to have the fixtures shipped.Ive contacted numourous lighting supply warehouses and they all said that the major manufactures dont make them in 120 volt.If there is a no-name brand out there that makes these in the 120 volt flavor, please do tell.