A security device to monitor object displacement and unauthorized removal from an enclosure. A two-layer adhesive is supplied on the marker, the first stronger adhesive for affixing the marker on the object, a second, weaker adhesive with lower tear resistance than the first which modifies an...http://www.google.de/patents/US5767772?utm_source=gb-gplus-sharePatent US5767772 - Marker for an article which is detected when it passes through a surveillance zone 
