Well, although I have not heard back from Jimmy Koh (which is not surprise given the terrible effect of Sandy), I have obtained Tony Hilton's Bronica book, The early history of Bronica, and his book states that the EC light meter takes a 6 volt battery, e.g., PX28LB 6V Lithium Battery, so apparently the early models of the EC light meter use only 3 volts (as stated in Bronica's EC light meter manual and other sources), the "newer" versions take 6 volts. Hope this helps future users of the Bronica system. Jon