Cobalt Free Humidity Indicator Cards are a series of moisture sensitive spots,that respond to changing levels of humidity by a visible change in colour from blue to pink.Humidity Indicator Cards are  used mainly in the dry packing of moisture sensitive devices.. When you open the moisture bag you will see from the colour of the spots that the bag has been correctly sealed and the silica gel or desiccant has functioned correctly.The 3 spot 5%, 10%, and 60% complies with IPC/JEDEC  J-STD-033B. The 4 spot is 10%,20%,30% and 40%. 

For a moisture sensitive device to be fully protected, it should be packed in a moisture barrier bag with a sachet of silica gel and a humidity indicator card.

 Cobalt Dichloride Free Humidity Indicator Cards,