DON'T KNOW MUCH ABOUT THEM got them in a box lot , will be happy to answer any questions look to be in good shape and turn over by hand uniformely permanent magnet  servo motor tack,,, part #0723-44011  ser #00006  date code 120 the larger of the two, smaller dia motor  part #0670-08-022 ser # H00125 date code 121,,, price150$ ea