Designed to work where incandescent reflector bulbs are used. They use 75% less energy than incandescent reflector bulbs and last up to 12,000 hours for tremendous savings when you consider sourcing replacement bulbs and the labor to install them. For use with recessed lighting fixtures and track lighting fixtures. Provide excellent color rendering, they are often favored for task lighting. IMPORTANT NOTE: Unless the CFL is specifically labeled to be dimmable, DO NOT use with a dimmer, or you can create a fire hazard.