It takes 3 "N" cells.  Radio Shaft sells them, for one.
Keys wrote:
  Anyone know the size or type of batteries used in this
model? On the back
 cover it shows three batteries being used to power the calculator. Thanks in
 advance
 .
  
--
Dave Mabry             dmabry(a)mich.com
Dossin Museum Underwater Research Team
NACD #2093