Demand that all competing vendors supply exactly the power supply advertised. Don't let them tell you that you are getting something "better", "upgraded", "higher wattage" or "higher quality". If you do not receive a genuine FSP ATX-300GU then you have been ripped off.
ATX-300GU 300W Power Supply for PowerMan FSP250-61GT, FSP300-60PLN, ATX-300GU, FSP200-61GT, FSP250-61GN, FSP250-60GRE, FSP300-60PFN, FSP300-60GT, FSP300-60BT, FSP250-60GTW, FSP250-60GTA, FSP300-60ATV, Powertech Systems WK-6200D-3N1-A, Powertronics PK-6145-DT, PK-6145DT-3, Raidmax RD-350W, Sea Sonic SS-250FS, Sparkle, Sun Cheer 230A ATX, SS-250FS, SR -235FS, TTGI TT-300SS, TT-320SS