Metal halide lamps are comparable with high-pressure mercury vapour lamps in design and function. They additionally contain a mixture of metal halides. In addition to increasing the luminous efficacy, improved colour rendition is also attained. Due to combinations of metals, an almost continuous multiline spectrum is produced. Metal halide lamps are available in the light colours warm white, neutral white and daylight white. Compared to quartz technology, the lamps with ceramic discharge tube feature higher luminous efficacy and better colour rendition due to the increased operating temperature.