The NICOR DLR4 LED Retrofit Downlight was made to fit all 4-inch housings. It includes everything you need to make the switch to LED and start saving money on electricity. This LED connects to the existing Edison base within the housing and mounts directly inside. It's that easy. Installation takes 30 seconds and the LED provides over 600 lumens of light output and lasts 10 times longer than traditional lamps. Protected by NICOR's 5-year limited warranty.