The Super Adjustable was manufactured from 1968-Q3 (N3) to sometime in 1975, the exact quarter is unknown.
It replaced the Slim. The brass handle was replaced with an aluminium one and the "rounding" on the head is slightly flatter.

How does it shave?
Its a mild to early medium shaver.
I find it to be the best shaver of the "common" Gillette Adjustables.