Apparatus for visually indicating elapsed time by a color change

摘要: Apparatus for visually indicating elapsed time by a color change is disclosed comprising first and second chromophoric compound that are combined with one another through matrix which controls the rate of combination compounds so body produced reaction over period may be adjustable from anywhere about to thirty days. The device comprises transparent container having rupturable capsule therein in composition contained. A surrounding also container. secured surface means mechanical fastener or an adhesive layer.