<P> Yet another method is the attachment of items to a larger immobile object, usually furniture or walls . </P> <P> Items with specific functionality can often be disabled to prevent use of the item should it be stolen . The anti-theft system can require disabling on every use, or enabling when the item should be secured . Disabling the anti-theft system is usually done by requiring identification of the owner at some stage of use . Identification can occur physically or through other methods (physical keys, numerical codes, complex passwords, biometric identification). This can work even retrospectively: as a stolen credit card can easily be invalidated with a phone call to the issuing bank, the motivation to steal one is reduced . </P> <P> In the case of vehicle theft, the best deterrent to theft is in the installation of an approved vehicle anti theft passive immobilizer . Many vehicles have OEM (factory installed) units and afford protection through the ignition system . OEM immobilizers function through the ECM / PCM (computer) under the hood of the vehicle . In general terms, the RFID tag attached to the key must be read by the ECM in order to allow ignition to occur . Unfortunately, organized crime thieves are able to bypass these systems and steal any vehicle at will . An approved immobilizer uses a 3 circuit isolation system which thwarts even the most experienced thief . </P> <P> Security tags are devices that are attached to products to prevent shoplifting and are often used in conjunction with an Electronic article surveillance system . SelectaDNA or Smartwater are such security tags - a forensic fluid which contains millions of tiny fragments which have a unique number called "SIN" ("SelectaDNA identification number"), and registered in a national police database together with the owner's details, is etched into each of those particles . </P>

What is an anti-theft device on a car
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