Firewall WiFi protection

Can anyone provide clarification on the following?

Does the FREE version of CIS provide protection when connected via WiFi
I ask the question because in the product descriptions COMODO state that among other things one the differences between FREE and PRO version is WiFi support.
Or are they talking about an additional feature i.e. encrypted trasnfer.
So the bottom line question is "is it safe to use CIS FREE version when connected via WiFi.

Thanks in advance