The Phantom Series is architecturally designed for unobtrusive use in walls with cavity (dry-walls with 4-inch studs) or un-insulated ceilings with horizontal beams or T-bar structures. In normal conditions (stand-by) the unit is completely concealed in the wall or ceiling. In case of power failure the door of the unit rotates open 180 and exposes the emergency lights (two high-efficiency MR16 lamps) to illuminate the path of egress.