The much-rumored Sony Xperia Z1S smartphone is now finally official and it will hit the U.S. as a T-Mobile exclusive.

Sony launched its Xperia Z1 handset back in September, but the smartphone never made it to the U.S. When rumors first started to emerge about an Xperia Z1S model, the smartphone was thought to be a Mini variant of the flagship Z1. As it turns out, the new Xperia Z1S is actually the U.S. version of the Xperia Z1, and sports some slightly enhanced features compared to the original flagship.

The Xperia Z1S, for instance, now boasts IP58 certification, which means that the smartphone is completely waterproof, able to withstand being submerged in up to 4.9 feet of water for up to 30 minutes. The handset is also dust-resistant with IP55 certification.

"As a waterproof smartphone complete with the best of Sony's technology, Xperia Z1S breaks the mold of not only what you can do with a smartphone, but where you can take it," touted Sony Mobile Communications U.S. President Ravi Nookala. "Building on the momentum of the successful partnership for the launch of the Xperia Z, T-Mobile's shared vision of delivering an uncompromised mobile experience makes them the perfect exclusive partner to bring Xperia Z1S to the U.S."

The T-Mobile-exclusive Xperia Z1S also keeps all of the high-end, popular features of the original Xperia Z1, including the powerful 20.7-megapixel camera with Sony's f/2.0 aperture G Lens and BIONZ image processing system with enhanced auto-focus. The smartphone will also pack special camera-centric software such as Social Live, which allows users to broadcast video directly to Facebook, and Timeshift Burst, which can capture a whopping 61 images in just two seconds. The handset also has a 2-megapixel front-facing shooter.

Specifications of the Sony Xperia Z1S include a 5-in TRILUMINOS display with a full HD resolution of 1920 x 1080 pixels, a powerful 2.2GHz quad-core Qualcomm Snapdragon 800 processor, and 2GB of RAM. The smartphone also features 32GB of internal storage capacity and a microSD card slot for additional memory of up to 64GB. On the software side, the Xperia Z1S ships with Android 4.3 Jelly Bean out of the box, with an update to Android 4.4 KitKat expected shortly.

Wireless connectivity options include 4G LTE, Wi-Fi 802.11 a/b/g/n/ac, Bluetooth 4.0, GPS, and NFC. A 3,000 mAh battery will keep things up and running.

The Sony Xperia Z1S will launch as a T-Mobile exclusive on Jan. 22 and will cost $528 outright or $22 monthly installments spread over two years. T-Mobile is now allowing interested customers to pre-register for the Xperia Z1S, but pre-orders will not go live until Monday, Jan. 13. In the meantime, check out the video below to see the smartphone in action.