It's part of a set of "combiner" robots sold by Matchbox under the Robotech name called Robolinks. There were several bots in each set with connector components that could be used to build bigger bots, vehicles, etc. Kind of like a Lego-style toy where the main bricks are bots. Do a web search, and you'll find the sets. I have one for sale on my sales thread.
I had that one's Counterpart with two Squares on its chest instead of just one rectangle. It was part of a series of Building toys Called "Blockman" from Takara from around the same time as Transformers. What you have is a Component part for a bigger toy Basically you plug these figures into each other and assorted specialized pieces and you could build like some bigger robot or something. As you can probably tell, Blockman didn't last as long as Diaclone or Microman (The two toylines much of the 1984-1985 Transformers were composed of) did mostly due to the fact that the Component robot pieces didn't couple with each other very solidly and the end result wasn't too appealing either.
