X-MEM/80 for the TRS-80

They are professionally made and of good quality! I got the Model 1 and the Model III version, fully assembled, and they worked flawlessly. You can also purchase bare PCB- and kit-versions. 

The shop is here: 

https://shop.tucs-workbench.com/

Please note that I do not have any formal affiliation with Tuc's Workbench nor do I receive any of the proceeds. I simply mention it here because I think that it is neat that it is possible to purchase X-MEM/80s - not everybody can make their own. But know that everything is OpenSource on Github. 

X-MEM/80 is having its 5 minutes of fame! Woohoo!

https://www.trs-80.com/wordpress/