I own a CZ7A Pro, which was the predecessor of the CZ-70. The 70 has the 4th tone that the 7a and 7aPro doesn'tThe 4th tone is for the square tab icon on 7a and 7a pro.I really don't need the 4th tone I just dig the square tab. I am not sure of the difference between the 7a and 7aPro except I think the 7a may use 4 AA batteries and the machine would run the batteries down if left in machine.The 7apro uses 2 9 volt batteries and you can leave them in there.
I am not sure if your looking to buy new or used, there are still some new CZ 70's around. Used, you probably can pick up a 7aPro cheaper than a 70 used I hope this helps, HH