We also performed simulated ‘thefts’, ensuring that for units equipped with proximity tags, we drove off with out them and produced guaranteed that we travelled nicely outside of any geofences. Some (even though none tested in this article) will insert VHF monitoring together with GSM positioning which provides extra detail https://www.trackerfit.co.uk/blog/stolen-car-recovery-why-24-7-monitored-trackers-make-a-difference/