Question about Solis Type 440

I did a little research. The Solis site only says:

Solis Typ:
440
Item no.:
968.51 / 968.50 / 968.55 / 968.52 / 968.56

What I found out:
968.51 = Black, 1.8 m cable.
968.52 = Black. 2.8 m cable
968.55 = purple, 1.8 m cable

The other ???? I can't see the real difference between the 968.50 and 968.51, except that the 968.50 is a bit cheaper. I assume that it does not have something that the 968.51 has.

Anyway, we (or rather my wife :-)) have been using the 968.51 almost every day for about 3 years. My wife is very satisfied with it.

Greetings, neptun88