PadFone X offers two mobile devices in one (pictures)

LAS VEGAS -- In partnership with AT&T, the Asus Padfone X will be available to the US market later this year. It features a Snapdragon 800 processor inside a 5-inch smartphone -- that of which can then connect into a 9-inch tablet.

Thanks to the addition of Android 4.4 KitKat and Voice over LTE (VoLTE), which will support voice calls over the data network, this carrier-branded version is an even more promising performer than its cousin, the Asus PadFone (September 2013).

Apart from OS and this carrier partner, the specs we know of so far are very similar to September's unlocked, global model.

The PadFone X includes a 5-inch, 1080p HD smartphone slides into a connector bay on the back of the tablet docking shell.

The phone sports a 2,300mAh non-removable battery and Qualcomm Snapdragon 800 processor, which the tablet will use for its own processing power. The pad will come with its own 4,990mAh battery, however.

The tablet also features dual front-facing speakers, which is ideal for media viewing. Both the devices looked to have pretty solid build quality, but of course, we won't know for sure until we get a review unit in our offices.

The tablet portion of the PadFone is smaller this time around, just a 9-inch HD screen (with a 1,920x1,200-pixel resolution) rather than the 10.1 inches before. That'll place the PadFone X on the larger end of the tablet scale compared to small-size devices like Nexus 7 and iPad Mini tablets.

The PadFone X's eventual success or failure on AT&T will come down to price and if buying the one-two combo makes financial sense for those who are also interested in a tablet form factor for travel or home.