This is an antique farm or ranch tool.  This is an in-line tightener to remove slack from a wire fence.  This tool has a Cast Iron with a tie ring at one side and two arms for wire spool.  Each arm has a hex shaped opening.  Pin has square shoulders for wrench, and hex shoulders to lock into the holes of the arms, when removing slack from the fence.    Tool is not maker marked.  It was designed to be placed on a round iron post.   Tightener could the be used in the future to remove more slack.   Tightener is 3-1/2" in length, and is in  good used condition.  There are no off odors.