They were an addon- I managed to salvage as badly yellowed mac 512 from an electronics recycler, it was in the bag, I paid a whole 10 dollars for it, Just so I could have the bag. Then this mac 512k popped up, I already had one, but this one fits nicely in my collection of compact macs. Considering this was used on the development of Aldus Products.

I need a HD20 For it now.