For US/non-CE applications:
Black S4HID 150 Watt ballast is 7060K1015 (S4 HID BALLAST REPLACEMENT KIT UL). This kit includes the ballast, the burner, and the hardware to attach the ballast to the yoke.
For CE applications:
Black CE S4HID ballast: ETC part 7060B2005 (S4HID 240V 150WATTS BLK)
White/Custom ballast: ETC part PS333 (BALLAST HID 150W 230-277VAC)