I don't know all the differences, but you can check for yourself here:
http://www.hafler.com/home/
Click on Tech Support and then Library Archives. They have manuals for all 3 models in PDF format. Good luck with your research.
David
http://www.hafler.com/home/
Click on Tech Support and then Library Archives. They have manuals for all 3 models in PDF format. Good luck with your research.
David