This is the device that launched the app. It was buying a couple of these off Ebay that made me want to create an app to help send the SMS commands.
The device was marketed as the Byte TK 102B and is not a “genuine” Xexun TK 102 (I’m not 100% certain of the history but the consensus seems to be that Xexun were the first manufacturer to produce this unit).
The user manual for this device is available here: TK-102B Manual
The format of the commands for this unit are different to the ones that the Xexun uses and some of the later revisions of the unit.
if the manual for your unit shows the geofence command as looking something like this:
and the tracking/auto track command looks like this:
Then your device is probably compatible with this unit and you should choose TK-102B as your device type.