This is old school vintage stuff.  These are hard to find.  I do not know if this is self-operating or not, but the Powers 595 Self-Operating #11 is the closest I could find to this unit.  There are no parts numbers on this.  It measures from 25 to 250 degrees F.  

There is some grease, dirt and grime on these from sitting on Trane Company parts shelf for a long time.  The one unit may or may not work.  You are buying these AS-IS.