| abstract |
An on demand useful life indicator (10) and method providing a uniform visual change. The indicator (10) attachable to goods or worn. This indicator includes a base (12); indicator material (14), impermeable adhesive (16), and a co-layered covering (18). The indicator material (14) provides a visual indication when exposed to a selected component of an ambient fluid.. The indicator material (14) is intimately fixed to one side of a second layer (22) of the covering (18) in a selected pattern. The adhesive layer (16) is applied in a selected pattern between the base member (12) and the covering material (18). A permeable second layer (22) of the covering (18) is adhered to the adhesive layer (16) allowing an impermeable first layer (20) to be selectively removed therefrom. The useful life indicator remains in a selected state of dormancy until removal of the first layer (2). |