Abstract: An anti-theft tag has releasably connected male and female portions. The male portion is in the form of a pin. The female portion has a retainer and an insert loosely received in a housing. The insert has a cup-shaped recess facing the retainer with a generally conical side-wall tapering outwardly towards the retainer. The insert and retainer have coaxial bores which receive the shank of the pin. Four retaining balls are received in the insert recess and are urged into tight frictional engagement with the pin shank by the retainer which is biased towards the insert by a coil spring. Once the pin is engaged in the insert and retainer bores it is held by the retaining balls and cannot be removed except by use of a special tool. The floating insert prevents by preventing unauthorized removal of the pin separation of the insert and retainer as a result of a sharp tap to the housing.