They are a zinc air battery. Yep, I know it sounds weird... but they have a very long shelf life and are not activated until you remove a covering off their Negative terminal. You're supposed to leave the the covering off battery for a day before you put it into service.
Sorry URL didn't work... Instead use Google images search for 1.35V Wein Cell
(They're used in my Minolta SRT 101 and my Yashica Mat 124G)
Now my Yashica Electro 35 uses a different battery (5.6V Mercury) that I sub with a 6V PHO 0230 and find it is close enough for the old camera to work properly.
Hope this helps.