21690 is a Metal Halide Halogen Lamp with reflector, combine the HPS technology providing stability, efficiency & uniformity and the metal halide technology bright white quality light to produce highly efficient light sources with good colour rendering and consistent colour performance through life. The metal halide lamps, made with quartz arc tubes, are prone to colour shift through life and lamp-to-lamp colour variation. Some of the dose, e.g. sodium (an important component of metal halide lamps), can migrate through quartz to cause colour shift and loss of light through life. The ceramic arc tube resists this material loss, can be manufactured to tighter tolerances and withstands a higher temperature to provide a more constant colour. It is suitable for retail, office, Commercial areas/city beautification/architectural and hospitality.