Hi Jim

The Modus is basically the DM1 unit. I would recommend that unit other than it does not self-zero. At the last symposium I presented a session on pre and post diagnostics that included a comparison of digital micro-monometers and their cost. Unfortunately my favorite, the Energy Conservatory unit, has been upgraded to a much more expensive unit but there are other choices that self zero. The ability to measure to 0.1 pascals or 0.001" is a minimum requirement. I posted the talk I gave to a page on my web-site and the 2nd slide compares the different units I found that were available. Check them out at this link.

https://www.wpb-radon.com/PFE_Communication_Test.html

Thanks Bill. I attended that session but did not recall that information until I saw the slide.