Abstract: A theft detection tag is formed from first and second sections which define a loop for receipt of an article part and which are connected by a coupling adapted to be quickly activated so as to change the loop and thereby permit quick attachment and release of the tag and article. In a first form of the tag, the first tag section includes a body having an upper end and the second tag section includes wedge means movable within the body to form the loop with the upper body end. In a second form of the tag, the first section includes a flexible member having at one end teeth and the second member includes a body with a channel for receiving the one end of the flexible member.