There are many lines of Fissler now that might have a certain technology that would give them an advantage for some uses. There are some lines in the past that had some interesting characteristics as well.
Fissler skillets

My MIL and SIL had some pans made in the 70s by Fissler that were enamel over steel, but I never did like them that much.
Fissler Asta

If you are just comparing the pro line, old and new, it is hard to tell as the amount of aluminum in the base as it is proprietary. Possibly someone might know on the Chowhound cookware forum. One thing to look at to compare old and new is if the handles are spot welded on the old as they are in the new. Since the company has made cookware for a long time, that change could have been 70 years ago, if they were riveted at one time. Some people prefer the spot weld because the inside of the pan is smooth others prefer the rivet because of the strength. If you can find some of this line on the secondary market, you would save a lot of money.

I lost hope someone would respond.

This forum is kinda slow.

thanx for responding.

I am looking at pro, pressure cookers and maybe steelux

I know steelux is not very old but if I find a good deal....