Carrier targeted Pops are available with CPM Inventory.
You can now buy only 3G traffic and can exclude Wi-Fi traffic, if required.
Also you can choose some specific carriers from the list which converts well for you.
As its highly targeted traffic, volumes gets low when you opt for this, so bidding needs to be good here.
US traffic is available here along with few other geo’s, inclusive of Adult and mainstream.
For getting started, reach at info@cpminventory.com
or Skype @ popundermedia