GE 18904 MVR400/U/ED28 400 499 watt Metal Halide Light Bulb at eLightBulbs.com

Lumens (light output)

This refers to the literal measure of the light-output of a particular light bulb, measured in the number of lumens.

Watts (Energy Used)

"Watts" is the term applied to the amount of energy required and used by a particular light bulb. It is an international system unit of power equal to one joule per second. Contrary to popular belief, the wattage of a bulb does not directly measure the brightness; the "lumens" of a light is what defines the actual light output.

Average Lifetime

This refers to an average lifetime rating based on large quantities in test groups. This testing takes into account usage of 3 hours per start for fluorescent lamps and 10 hours per start for HID lamps.

Volts

Voltage is a measure of electrical potential.

Bulb Type

The "Bulb Type" is typically a combination of the style of bulb as well as the width of the bulb. Usually, the first couple letters will indicate the type; "G" would indicate "Globe", "PAR" would indicate "Parabolic Reflector"... The numbers indicate the diameter of the light bulb in eighths of an inch; a "G40" would be a "Globe" style that is "5 inches" in diameter.

HID (High Intensity Discharge) Light Bulbs > Metal Halide > 400 - 499 watt > GE 18904 (MVR400/U/ED28)

400 watt ED28 Mogul Screw (E39) Base 4,000K Clear Multi-Vapor Quartz Metal Halide HID GE Light Bulb (Enclosed Fixtures Only)

GE 18904
MVR400/U/ED28

HID (High Intensity Discharge) Light Bulbs > Metal Halide > 400 - 499 watt > GE 18904 (MVR400/U/ED28)

400 watt ED28 Mogul Screw (E39) Base 4,000K Clear Multi-Vapor Quartz Metal Halide HID GE Light Bulb (Enclosed Fixtures Only)

GE 18904MVR400/U/ED28

GE 18904
MVR400/U/ED28