it's 4, 2kw PSUs from the IBC bladecenter. Absolutely rock bloody solid power supplies. I'm had them running 6 antminers each actually, I keep it at 4 each for better power efficiency. I made more than I need, so I'd imagine I'll be selling the extras, with the power distribution blocks as well. (Can run 6ants from 1 block) Complete plug n play kit if anyone is interested. They only run at 208v-240v single phase.