Front fork adjustment on an '85

[balky1]

Well, after a couple of years owning the bike I found out there are two things I can turn to adjust the front fork  , but that's not mentioned anywhere in the Clymer. Clymer mentions spring preload adjustment made by turning the adjuster (marked with a red dot) with flat screw driver. That's what I knew before. But I saw that I can turn the outer ring that also has a marking on it (small red slot) without turning the inner one for screw driver, thus being independent, and also has 3 clicks. This part can be turned with a 12 mm allen key. What does this guy do?!
I suppose one is for preload and the other for damping or am I wrong?

Thanks!

Ivan

[4everFJ]

Here you go:

[balky1]

Here you go:

Yep, just as I thought! Thank you!

Ivan