Here are 4 San Francisco wooden insulators in my collection. The one on the left says 8-30-70 Phil Harding $650. on it's tag on the bottom. The one on the right says type II #13170 . Middle left says type III. Middle right has no info. Does anyone know what this information means. [ I know what the $650 means ] I know Phil Harding was a friend of my father's.