Osram Sodium lamps have a full spectrum with a large amount of red for good flowering and fruiting
It also has a high lumen output with large amounts of yellow and orange which is where you get most photosynthesis per watt; in other words this is the spectrum of your light your plant uses most efficiently to produce energy through photosynthesis
This accounts for the vigorous growth rates and high yields associated with high levels of sodium light
Always allow bulbs to cool after switching off before replacement.