Patent attributes
A closure device having first and second fastening strips arranged to be interlocked over a predetermined length is provided. Each of said first and second fastening strips includes first and second closure elements separated by an intermediate area, wherein the first closure element on the first fastening strip is arranged to be interlocked over a predetermined length with the first closure element on the second fastening strip, and the second closure element on the first fastening strip is arranged to be interlocked over a predetermined length with the second closure element on the second fastening strip. Each of the closure elements may be colored with a colorant. For example, the closure elements on one fastening strip may be colored with an opaque pigment, and the intermediate area on that fastening strip may colored with a first translucent pigment. The closure elements on the other fastening strip may be colored with a translucent pigment, and the intermediate area on that fastening strip may be colored with a second opaque pigment. When the closure device is occluded, the colors of the first and second pigments combine to cause a change in color. The change in color may be observed from either side of the closure device.
