We all have things that should avoid humidity when we have them in secure storage. This device is almost as important as the safe you lock them in. Simple to use and recharge, they absorb a ton of moisture and keep your documents and weapons out of the humidity. I had to charge each of them upon arrival which isn't hard. Simply plug them in overnight, the indicator turns blue and you are ready to go. I am not sure how their little wire hanger is supposed to work and have had to work out some other options but the device itself is exceptional.