Both CA's say they detect ambiant CO and natural gas leaks.

-Now with the testo do you have to buy a separate probe one for ambiant CO and one for Natural gas detection?
-Is this true as well with the Bacharach?

To me it sounds like you need extra probes for the Testo but the not the Bacharach.
These specifics are not very clear at all in the descriptions of the CA's, hoping some of you guys can clear this up for me.