Retrofit LEDs. Nora Lighting recently added a 4-inch 10-watt model to its Diamond Series of LED retrofit downlights. Like the series’ 5-inch (12W) and 6-inch (12W) fixtures, the new model can be installed in an existing Nora or third-party housing and is energized through a medium screw base or a Gu-24 adaptor. Prices for Diamond Series downlights run from about $120 to $170. Nora Lighting, 800/686-6672,