different models; same description

> What is the difference between the C7100V and C7100V-1AZNAS
> modem-router-telephony gateways?

   One's sold by/through Amazon?

      https://community.netgear.com/t5/x/x/td-p/981232

   The "1" in "1AZ" seems to refer to a "v1" hardware revision.  On a
non-Amazon device, that'd typically be "100", "200" ("v2"), or similar.
The "NA" in "NAS" seems to be "North America".  The "S" is a mystery.