Cobalt Chloride Humidity Test Strips, Pack of 1,200

This is a limited use product.It is very blue when it is wet and pale when the humidity is low.My problem is that they do not provide a color chart to show howthe strips color is equal to anything.My salt shaker's strip is blue and sure enough the damp salt has plugged the holes.If they are so insecure as to not provide a color chart.I suspect the quality or usefulness of this product.