A standard recessed lamp is a box-type reflector that is connected to a cable projecting out through a hole in a wall, and then fitted to the hole and secured in place. In order to ease installation and avoid hitting underlying structure it is standard to keep the entire fixture within the bounds defined by the hole, although some fixtures do have connection boxes that project laterally behind the installed fixture.
One such fixture, as described in Austrian Pat. No. 323,961, has a reflector pan or box provided at its ends with sockets for the bulbs. This structure therefore has the further disadvantage over the above-described system that the fully visible sockets are rarely attractive and reduce the effectiveness of the lamp by reducing the space available for bulbs.
Furthermore such devices often are quite difficult to install. Special clamps and clips must be manipulated with tools to secure a tight fit. Only the most complex and difficult-to-use systems can be used with a wide range of wall thicknesses.