So either the ballast has a switch on the back of it.. making it a switchable ballast. Or it's a digital Ballast.

Digital Ballasts allow you to put both MH and HPS bulbs of approximately the same wattage into the same ballast. Meaning if you have a 400watt digital ballast, you CAN put a 430watt SonAgro bulb in that 400 digital Ballast.

I'd confirm what the auction is offering if i were you..
BobBong Reviewed by BobBong on . used hydrofarm sunburst question Hey what's up guys. I came across an ad on craigslist for a hydrofarm sunburst 250 watt hps for $200. His ad also says that the unit comes with 230 watt mh bulb. I've been looking all over the web and can't find a 250 watt switchable sunburst unit. He claims the unit is switchable and can use both bulbs. I just want to cover my arse and don't get ripped off. I think its a steal for 200. Lot of young kids who don't take anytime researching buying equipment and failing on their 1st grows. Any Rating: 5