Item Code: 23-5001492

Ushio Part #: UHI-S400AQ/10/CWA

* Probe start version designed for M59 ballast
* Made in Germany
* Ushio 10,000K is the general standard for 10,000K color in metal halide lamps.
* Mogul Base.
* Crisp White.
* Approx. length from end-to-end: 10 1/2"

FAQ:
Q. What are the ANSI codes for Probe Start and Pulse Start ballasts?
A. Probe Start ANSI Codes for Metal Halide lamps: M102=150W, M57=175W, M58=250W, M59=400W, M47=1,000W.
Pulse Start ANSI Codes for Metal Halide lamps: M85=70W HQI, M81=150W HQI, M137=175W, M138=250W, M135=400W.
Q. Why do 10,000K bulb all have different colors? Shouldn't they all be the same if they're marked "10,000K"??
A. Color Temperature ratings (i.e. "K") is more of a marketing term than a true scientific measurement for color. There are far too many variables when it comes to an accurate "K" rating. Bulbs of the same manufacture can color up differently over time, as the ballast ages (although this is generally not noticeable by the aquarist). This is why most "K" is used as a reference rather than an absolute. The higher the K, generally the more "blue" the bulb becomes. Sunlight is about 5,500K.