Yeah, no windows within 50’ of my space unfortunately.
The carbon filter inserts on this are made of metal and weigh about 10lbs each. They’ve got heavy duty rubber gaskets all around that create the airtight seal that forces all of the airflow through the carbon. DIY might be tough, one leak and everything starts taking the path of least resistance …
Carbon is pretty much carbon, but I believe it’s the seals and gaskets and the tight tolerances that helps this work so good, plus the large surface area of the carbon filters.