Buy One per Foundation Area (see below Foundation Areas)

You will want to buy one test kit per "foundation area" your home has.  

For instance, if you have a basement and one crawlspace, you will need two kits. 

If you have just a basement, you need only one test kit.

If you have a slab-on-grade area (no basement nor crawlspace), and a basement, and two  crawlspaces, you need four kits. 

And so forth. 

Don't be fooled by the simple, low-cost wrapping and reasonable pricing, these are very high quality, highly accurate, radon tests.  

They are used by professionals and organizations around the world. It is the most used radon test on the planet. 

The top-tier evaluation lab has same-day analysis during weekdays.