Sylvania Grolux 600 watt Son T Plus HPS Lamp
Sylvania Grolux 600 watt Son T Plus High Pressure Sodium Lamp
The Sylvania Grolux HPS bulb was designed specifically for greenhouse supplementary lighting.
It has increased blue light and the highest PAR rating.
This is the hottest bulb right now and is consistently out-performing the Hortilux.