Abstract: A novel locking mechanism and specific applications for same are disclosed. One aspect of the invention provides a product security system having a locking mechanism for preventing sliding movement between a slidably juxtaposed product container and product container locking structure, and a separate decoupling unit. The decoupling unit has a frame adapted to receive the slideably juxtaposed parts, and means within the frame adapted to disengage the locking mechanism, thereby permitting sliding decoupling of the parts. The locking mechanism has a magnetically attractable pin in a blind hole in the first part and a detent opening or recess in the second part. The pin is moveable between a first position in which the pin enters the detent, thereby preventing sliding movement between the first and second parts, and a second position in which the pin is retracted into the blind hole from the detent, thereby permitting sliding movement. Means are provided for biasing the pin into the first position.