Physical crime controls include all types of barriers, such as safes, vaults and locked doors that prevent someone from taking protected property away. Perimeter controls can permit entry but prevent egress via the same path. Guards may approach suspicious-looking persons, or anyone wearing clothing that might be deemed to be a disguise. Controls may include alarms, gongs, “screamers”, strobe lights and similar devices that call attention, locally, to the fact that someone has tried to access property that has been protected. In addition, remote central alarm stations, which may be silent, can be authorized to automatically send authorities to the point of attack once security is breached.
Specific physical controls might include imbedded devices that set off alarms if not de-activated at the point of purchase, which are quite common in retail environments, and things like dye packs that may be embedded in cash handed to a robber during a hold-up.
Modern paper currency includes several specific features to help distinguish a real bill from a counterfeit. Paper cheque blanks can be ordered with several hard-to-duplicate features, thus reducing the exposure to forgery loss.