While the Bluetooth versions of Samsung’s new Galaxy Watch were announced alongside their prices and release dates, details for the cellular versions were left vague. That changed today: Samsung has revealed that the LTE Galaxy Watches will each sell at a $50 premium over Bluetooth models, and will start to ship during the “week of September 2, 2018.”

The Galaxy Watch is the renamed sequel to Samsung’s Gear S3 series of smartwatches, now available in smaller 42mm and classic 46mm sizes — the former with 45 promised hours of battery life versus the latter’s 80 hours. Each version is watertight to 50-meter depths and comes with 4GB of onboard storage space.

Apart from the size differences, the internal hardware diverges between the Bluetooth and LTE models. Each Bluetooth watch has 768MB of RAM and depends upon a smartphone for some of its functionality, while the LTE models have 1.5GB of RAM and a cellular chip that lets the Galaxy Watch operate independently of a smartphone. Our earlier story on the Galaxy Watch goes into considerably more detail regarding their features.

With today’s announcements, customers now have the following Galaxy Watch choices:

During the Unpacked event where the Galaxy Watch debuted, Samsung said that all four U.S. carriers would be offering the LTE model, but as of now, listings are appearing on Samsung’s site solely for T-Mobile. Other carriers will likely offer the Galaxy Watch through their own stores and websites.

The T-Mobile models are listed as supporting 10Mbps data speeds on Band 2 (1900), Band 4 (AWS), Band 5 (850), Band 12 (700), Band 13 (700), Band 25 (1900), Band 26 (850), and Band 66 (AWS-3). They use an embedded SIM for network connectivity and are specified as no different in size or battery capacity from the Bluetooth versions.

But because of the high power drain of the cellular chip on the smaller 270mAh battery, Samsung only promises “up to 2 days” of typical usage for the 42mm LTE model, down from “up to 3 days” for the 42mm Bluetooth version. By comparison, both the Bluetooth and LTE 46mm models promise “up to 4 days” of typical use with their larger 472mAh batteries.

Samsung initially said that Bluetooth models would ship to preorderers starting on August 24. For advance orders placed today, the Bluetooth models are now expected to ship during the same week of September 2 timeframe as the LTE models. The company is currently offering a free watch band — one per model, including the Urban Traveller, Urban Dress Band, and Essex Leather band — as a preorder bonus.