The GSM version of the Motorola Moto G is already available for order in the U.S., and now so are removable back shells for the smartphone.

Motorola initially announced that its budget Moto G will hit the U.S. in early 2014, quite a while after launching in other markets. Just recently we reported that Motorola changed its mind and started taking orders for the GSM version of the handset, with shipping set to start on Dec. 2 in the U.S.

The Moto G comes as a mid-range, budget-friendly smartphone that borrows some of the popular features of the flagship Moto X and offers them in a more affordable package. While it doesn't sport the high customization features of the Moto X, the Moto G does allow for some personalization through interchangeable back shells.

Just in time for the holidays, Motorola's online shop now lists Moto G shells and flip covers in various color choices. Shipping will begin on Sec. 2, just as for the Moto G itself. The shells cost $14.99, while the flip covers are a bit more expensive at $29.99. While these prices may seem a bit steep for accessories, keep in mind that the Moto G costs just $179 unsubsidized.

For that $179, you'll get a decent smartphone with a 4.5-inch HD display with a resolution of 1280 x 720 pixels, a quad-core Qualcomm Snapdragon 400 processor clocked at 1.2GHz, and 2GB of RAM. The handset comes in 8GB and 16GB internal storage configurations, has a 5-megapixel rear camera with 1080p video recording capabilities, and a 1.3-megapixel front camera for video chats. Other specs include a 2,070 mAh battery, Wi-Fi, and Bluetooth. The Moto G ships with Android 4.3 Jelly Bean out of the box, but it will get an update to the latest Android 4.4 KitKat early next year.

The shells and flip covers for the Moto G are available in six colors: Chalk, Violet, Royal Blue, Turquoise, Lemon Line, and Cherry. As for the smartphone itself, the GSM model of the Moto G is already available for order, while the CDMA version will launch in January 2014.