The ceramic discharge metal-halide (CDM) lamp, often referred to as Ceramic Metal Halide lamp (CMH) or Light Emitting Ceramic (LEC), is a source of light that is a type of metal-halide lamp which is 10-20% more efficient than the traditional quartz metal halide and produces a superior color rendition (80-96 CRI).
CDM lamps use one fifth of the power of comparable tungsten incandescent light bulbs for the same light output (80–117 lm/W) and retain color stability better than most other gas discharge lamps. Like other high-intensity discharge lamps, they require correctly rated electrical ballast in order to operate.
This relatively new light source, touted for being compact, efficient, and powerful, is part of the high-intensity discharge (HID) lighting category, which offers the highest efficacy and longest life of any lighting type, and saves up to 90% of lighting energy when they replace incandescent lamps.
