Model 200 RAM
The model 200 comes with 24k built in, and supports up to 2 more banks of 24k in the form of ceramic dip modules that plug into the Option RAM #1 & #2 sockets.
= Original Ceramic Modules The original 24K module was Catalog Number 26-3866.
= DIY Modern Replacment
https://github.com/bkw777/TANDY_200_RAM
More info