The ASUS ZenFone 2 is officially in stock and ready to ship in the U.S. from Amazon, as the smartphone is now available in two versions.

More specifically, Amazon is now selling the 5.5-inch model of the ASUS ZenFone 2 either with 2GB of RAM and 16GB of internal storage capacity, or with 4GB of RAM and 64GB of internal storage capacity. Both variants come with Intel Atom processors clocked at 1.8GHz and 2.3GHz, respectively.

As a reminder, the ASUS ZenFone 2 made its official debut back at CES 2015 earlier this year, stirring lots of interest because it was the world's first smartphone to pack 4GB of RAM under the hood. Other specs include a 5.5-inch full HD IPS display with a resolution of 1920 x 1080 pixels, with a thin bezel of just 3.3mm and a pixel density of 403 ppi, a 13-megapixel PixelMaster rear camera with an f/2.0 aperture and zero shutter lag, as well as a low-light mode that increases brightness up to 400 percent without using flash, and a 5-megapixel front shooter with a "selfie Panorama" mode that can capture a 140-degree field.

Amazon is now offering the ASUS ZenFone 2 model with 2GB of RAM and 16GB of internal storage for $199, in either black or silver color options. The higher-end model with 4GB of RAM and 64GB of internal storage capacity, meanwhile, goes up to $299 and comes in silver, gold, and red color options. All models are unlocked, but it's worth mentioning that they will only work with GSM carriers such as AT&T and T-Mobile, not CDMA networks such as Verizon Wireless, Sprint, or U.S. Cellular.

Both models appear to be in stock at Amazon at the time of writing, with the mention that the ASUS ZenFone 2 with 4GB of RAM and 64GB of storage may require an extra day or two to process and ship. The model with 2GB of RAM and 16GB of storage is ready to ship as soon as May 20, for customers willing to pay extra for next-day delivery.

For more information or to purchase the ASUS ZenFone 2 from Amazon, head over to the product page at this link.