difference

Hi! What is the meaning of A129-G, VIOFO A129-DG, VIOFO A129-D? And how come on the website states: Input DC5.0V/3.1A via mini USB https://www.viofo.com/home/81-62-a129-front-5ghz-wi-fi-full-hd-dash-camera.html#/25-gps_module-included Same as this...