Buyers must prioritize network coverage (Global vs. Regional), as different constellations like Iridium (Global), Inmarsat (Global excluding poles), and Thuraya (Regional) offer varying reach. Key specs include Ingress Protection (IP) ratings (e.g., IP65 or IP67) for dust and water resistance, battery life (talk time vs. standby time), and GPS tracking capabilities. Ensure the device supports SOS emergency buttons and has a high-gain omnidirectional antenna for stable signal acquisition in remote areas.