Here is the techinical stuff I found on it:
[FONT=Verdana, Arial, Helvetica, sans-serif]
HIGH PRESSURE SODIUM: or HPS lamps emit a pink or amber light. They are used for lighting parking lots and other areas where the color of the light is not important. HPS units are much more efficient than MH ones, producing more light and less energy consumed. They are often used alone with no detrimental effect on the plants, and will promote faster plant growth than MH lamps during both vegetative growth and flowering. Combinations of bulbs are _NOT_ required, as the HPS lamp does produce all of the light spectrums necessary for healthy growth. There is a relatively new type of HPS lamp that has become available. It is called the...[/FONT] [FONT=Verdana, Arial, Helvetica, sans-serif]Son Agro lamp
Basically the designers of this lamp took a 400w HPS lamp, and added another 30W element to it, However, this new element puts out blue light, to help fill in the parts of the spectrum that a standard HPS is missing. We use SON-T Plus or Agro for years now. And the Bulbs are highly efficient and can be used for 6 crops.
[/FONT]
[FONT=Verdana, Arial, Helvetica, sans-serif]
[/FONT]