Thatcham Authorized: All of our trackers are Thatcham Accredited, Meaning which they are already issue to stringent safety testing by Thatcham, so as to find out their basic safety and performance. A GPS module communicates constantly with satellites to find out its specific place, though GSM technological innovation achieves this https://medium.com/@trackerfit11/caravan-trackers-and-why-they-matter-for-theft-protection-dd44f62fcad7