I recall the day I upgraded to that. Two drives!!! My Lord, you could actually make a backup. And you could have the O/S and programs on one disk, and data on another. It seemed like such a major step forward at the time.My first Mac was the dual disk, No hard drive 8k processor in 1986. I’ve been a Mac user every since.
I also recall my first external- only $700 for, IIRC 20 Megabytes!