Please note that this "GSM" A1428 iPhone 5 model was unveiled by T-Mobile and offers AWS (1700/2100 MHz) support on the T-Mobile network in the United States. As a result, it is not uncommon to see it referred to as the "T-Mobile" iPhone 5.

However, as first reported by Engadget, starting April 12, 2013, this model also was offered by AT&T in the US, which does not support AWS, as well as other carriers in North America (some of which do and some of which do not support the AWS standard). It supports LTE bands 4 and 17. Apart from AWS support on compatible carriers, though, it is identical to the earlier "GSM" A1428 iPhone 5, which EveryiPhone.com documents as its own model for clarity.

The iPhone 5 models, regardless of network compatibility, have a 4" (diagonal) widescreen multi-touch IPS LED-backlit 1136x640 native resolution (326 ppi) "retina display," dual cameras -- a rear 8 megapixel, 1080p "iSight" camera and a front 1.2 megapixel, 720p "FaceTime HD" camera, and 4G/LTE support, all packed in an aluminum "unibody" case with a glass front that is a mere 0.30 of an inch thick (color options include either a dark gray "slate" matte back and a glossy black front or a silver matte back and a glossy white front).

All iPhone 5 devices powered by a 1.3 GHz dual core "Apple A6" processor, has 1 GB of RAM, and 16 GB, 32 GB, or 64 GB of flash storage. It also supports both 2.4 GHz and 5 GHz 802.11n Wi-Fi and Bluetooth 4.0 as well as packs three noise canceling microphones, a bottom-mounted headphone jack, and a new USB 2.0-based Lightning port for connectivity.

Apple estimates that the iPhone 5 models provide "up to" 40 hours of audio playback, 8 hours of talk time on 3G, 8 hours of Internet use on 3G, 8 hours of Internet use on 4G/LTE, 10 hours of Internet use on Wi-Fi, 10 hours of video playback and 225 hours of standby time.

In the US, this "GSM" A1428 iPhone 5 was available with 16 GB, 32 GB or 64 GB of storage, for US$99, US$199, or US$299, respectively, unlocked -- but with a two-year contract -- on T-Mobile. Other pricing options were available and other carriers offered different pricing as well. In the US, unlocked and contract free, this model originally was available for US$649, US$749, and US$849.
https://everymac.com/systems/apple/iphone/specs/apple-iphone-5-a1428-gsm-lte-aws-tmobile-north-america-specs.html