Hello and welcome to e-Shepherd Solutions
In short, our TS-TAG was "The Smallest" GPS data-recorder unit we were making. It has now been discontinued and replaced with TM-TAG-Micro.
The TM-TAG is "The Medium" sized logger. This unit can be used in tracking most animals except for very small animals. It has been deployed as an ear tag and on collars for larger animals as well. It has superior sensitivity to the TS-TAG.
The TTX-TAG is "The Transmitter" logger. This unit can be used in tracking larger animals and gives option to download data remotely using bluetooth download station.
The TM-TAG is GPS data recorders and not transmitters. To retireve the data you will have to recapture the animal and download the data using provided USB cable and PC software