Vintage Apple Watch? Need information

Hi Everyone, my name is Caroline and i have come across this vintage apple watch! I would love to hear anyone who may know when this was made and what for? My research so far takes me to ebay, but all the watches on their have batteries which can be changed! This watch has a terminal that looks like it can be charged and i believe this is about 1980's.

If anyone can shed light on this i would be greatful, took into the apple store but no-one had ever seen one!

Sorry haven't cleaned it yet!