Galaxy 600w HPS Select-a-Watt. http://sunlightsupply.s3.amazonaws.com/documents/product/902517_Spec-Sheet.pdf Purchased by user at various locations. Average price $90-$120. Would I buy again? Absolutely Would I recommend? Yes No need to go into what a typical HPS ballast is anymore. Any quality ballast should do what it's supposed to. That shouldn't be remarkable. The ability to switch from 400w to 600w is pretty standard fare too. (Although the negligible energy savings switching down to a 400 vs 600w boggles me. Why do it?) The Galaxy has a typical 3 year warranty, which I've never had the opportunity to use. Which also brings me to the reason for the review. What is fairly remarkable is that I have 6 600w Galaxy's from both this model and it's previous generation. None have failed over several years of use and my gear gets thrashed around pretty good. Moves, garden tear downs, garden builds. Some have operated in ambient temps from -20F to 90F for months on end without fail. That they're cheap to boot makes it an easy buy.