Got this today via USPS a little banged up but went back together quite well and is now running. Unique pendulum hold down clamps for moving the clock without removing pendulum.
3 volts DC. Originally used the tall 1.5 volt cells mounted in the clamps seen on the right and left inside the case.
Yep. I have a Self Winding Clock Co. clock that came out of the local Western Union office that used the same batteries. In fact, still have those old batteries. I replaced them with two D cell batteries and they power it about a year before changing. Mine keeps perfect time. Nice clock you have there. Good condition. Congrats!