Immobilisers may also be a requirement to go Thatcham Classification one exams and need to be passively set – Meaning with none action from the driver – while at least two working units or one Command device useful for usual operation has to be isolated. S5 trackers (previously referred to https://medium.com/@trackerfit11/why-choosing-a-thatcham-tracker-strengthens-vehicle-security-6b79d8a9c256