OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Edgers Two Stroke Edgers Difference between these Tilt A Cut/Power Torque?

Hello all,
I'm lining up a couple of Victa Tilt a Cut edgers to look at but I'd like to know what the differences are between the models over the years so that I at least can pretend to know what I'm looking at when I go meet with the sellers.

I found these photos on the web and was wondering if someone knew the differences between these three?
Also, which model is the oldest one and if possible, which one has more parts still available?

cheers.

EDIT: (Images not working for some reason)