Enhanced Spectrum H.P.S. Bulbs

Enhanced Spectrum High Pressure Sodium bulbs are color shifted to product more blue than a standard HPS bulb. This makes them great for "one bulb grows all" lighting. They have great red spectrum making them a good flowering bulb, and additional blue spectrum making them an effective vegetative growth bulb, keeping the stems from elongating which can happen with standard HPS bulbs during vegetative growth.

Hortilux is one of the best

They are talked about all over this forum.