Abstract: A system for indicating that a container has been subjected to tampering includes a container having an outer surface with at least one central depressed region defined by opposed upstanding ledges extending sharply transverse to a plane of the depressed region and a continuous band of heat shrinkable material in general alignment with the central depressed region initially loosely encircles the container which, when heated, becomes shortened and congruently conforms to the outer surface of the container and is restrained against lateral movement beyond the upstanding ledges when removal from the container is attempted. The composition and dimensions of the band of heat shrinkable material are selected such that removal from the container cannot be accomplished without causing visibly apparent deformation or fracturing of either the band or of the container.