High Pressure Sodium (HPS), Metal Halides (MH) and Ceramic Metal Halides (CMH) are different types of High Intensity Discharge (HID) bulbs. Their wattages range from 50W to 1000W. The typical arc tubes in HPS, MH and CMH are made of translucent aluminum oxide, quartz, and ceramic respectively. Ballasts are needed to light up those HID bulbs. Since ceramic arc tubes will sustain much higher arc tube temperatures, the CMH bulbs will deliver better efficacy, color rendering and color stability.