High Quality Content by WIKIPEDIA articles! A multifaceted reflector light bulb is a format for halogen bulbs, made by a variety of manufacturers. MR lamps were originally designed for use in slide projectors, but are now used in applications including residential lighting and retail lighting. They are suited to a variety of applications that require directional lighting, such as track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting and bicycle headlights. Lamps are designated by symbols such as "MR 16" where the diameter is represented by numerals. Common sizes for general lighting are MR 16 and MR 11, with MR 20 and MR 8 used in specialty applications.