Believe this to be a 1975 Accutron 2210 (similar to the 263 in size and shape as per the attached ad).
This is my mother's watch. I finally pried it away from her for a cleaning and battery change, and I am going to put a NOS strap on it. She got it new in 1975 (for her 35th birthday), and has worn it daily since. Fantastic watch.