[Test-Equipment] Batteries for fluke 750A reference divider

[Gary Schafer]

Does anyone know what the number of the batteries are for the Fluke 750A 
reference divider?  They are 6.75 volt mercury cells. (2 ea.)

I understand that mercury cells are no longer available but with a part 
number I may be able to find a substitute battery.

Thanks
Gary  K4FMX