What does AC1900 mean in the router specification?

When shopping for a new router, I often saw specifications like AC1900, AC1750, AC1600, etc.  I am very curious to find out what it means. So I did everyone smart person would go: google it!

However, Google failed me this time. No matter what is the search term I use, I just can't find the defination for any of those numbers like AC1900. I have tried "what is ac1900", "ac1900 wiki". There are lots of results but no one explains what it means. It might be the whole world knows what is means, am I the only one left?

So I dig a bit deeper and find this arctile. I think it solved the mystery. 



"AC" number Find in Best case client speed
1750 AC routers



It turns out that it is the sum of the maxium speed of the dual band, no wonder I can't find it!

Hope you can sleep well tonight since the mystery is solved.  



Mini Router

I bought this Mini Router on the plane. It turns your network connection instantly to a WiFi network without configuration! It is very convient for travel, and weight 20g.

There are many modes of operation, which supposed can be a repeater as well for your WiFi network, but I have never be able to make it work. The documentation is pretty poorly written. I am checking both the English and Chinese version and still can't figure out what is the meaning. And the English version is different with the Chinese version!

5 stars for the product and 1 star for the documentation!