Mercury mixed-light lamps for open and enclosed luminaires. : HWL® lamps can be used instead of incandescent lamps because they do not need either control gear or igniters. : Factory and hall lighting with low-cost installations. Upgrading light fittings with high-wattage incandescent lamps. Factories and workshops. Pedestrian zones, public squares. Suitable for use in open and enclosed luminaires. Outdoor applications only in suitable luminaires.