Recessed lights are metal light housings that install above the ceiling line. Except for thin trim and part of the inner baffle, no part of the light is visible. Also known as can lights or downlights, they require extensive ceiling wiring. However, the junction boxes allow for light-to-light connections. This means that you are running only one cable, not several. Recessed lights on the consumer market generally vary in diameter from 3" to 6".