I own several Fujica ST-series SLRs and they are a
Another alternative would be the Yashica TL-Electro. I own one and the viewfinders are similarly bright. The TL-Electro also has mirror lock-up and a higher flash sync speed (nominally 1/125 sec, though likely 1/90 sec in actuality) than most M42s.
What battery does the Yashica TL Electro use?
Kodak S28 (or equivalent) silver-oxide battery. The same as a Fujica ST-801.