Product review (5 stars): Work great. Soon as a new pack goes in they ...
I use these to alert me when my silica gel packs are full so I can change for new. Work great. Soon as a new pack goes in they turn blue again. Have tested them with a thempetarure/humidity meter and they are accurate. Cheap and accurate. That I can see. Don't go bad. Longterm low cost investment that together with silica gel packs can save one thousands on ruined expensive gear.