Like the super thin trim, the Lotus LED Lights 4 Inch Round Slim LED Recessed Trim can also fit directly under joists for versatile installation. However, with a slightly larger, 1” thickness, it generates much more brightness than the ½” models. It comes with an isolated external driver (inside an included wire box), so that you can position light and driver separately if the structural layout of your home or business offers limited space. One driver for every fixture is required. No housing required.