There is provided a container having both male and female sealing regions disposed
about its periphery in a pattern making it possible to seal a container with another
container having substantially identical sealing regions. The male sealing regions
used in the practice of the present invention may take the form of a U-shaped ridge
which is undercut along at least one leg of the U. Typically, a container will
he thermoformed from lightweight thermoplastic material giving the U-shaped ridge
considerable flexibility. The female sealing regions used in the practice of the
invention may take the form of an undercut channel adapted to receive and match
the undercut U-shaped ridges found in the male portion of the container wherein
the walls and base of the channel are sufficiently flexible that the undercut portions
of the U-shaped ridge are urged into engagement with the undercut portions of the
channel and the crest of the ridge is urged into the channel.
