Last week, we reported that LG is planning to launch the first Windows Phone 7 Series as early as this September. The first prototype of this device has been shown by Microsoft during The Engadget Show.

The device sports a QWERTY slide-out keyboard, as well as a touch screen and the three standard Windows Phone 7 Series buttons: back, home and search. There are also buttons for power, camera and volume controls.

Engadget says the device is “just a hair thicker than an iPhone or Nexus One” and has a five megapixel camera with flash and a headphone jack.

Engadget also says that the device is still a prototype, and that anything can change from now to when the device is officially released.