Micro Essential Lab HJH-650 Hydrion Humidicator Paper for Detection and Estimation of Moisture 600" Length x 1/2" Width

I manage a seed bank and need to keep an eye on collections out in the field and then as they move around the lab. This is not a substitute for a high quality hygrometer but will help you keep a quick eye on collections that are in danger of mold or fungal growth, especially if you will be out in the field for days or weeks. Very handy!

I punch this out is small rounds to go in my compressor air driers and it works great.

I have used these for decades to keep an eye on humidity levels where I store archival prints and all kinds of photographic and electronic equipment. These simple indicator papers let me know the approximate humidity levels so everything stays safe and dry but not too dry.Anything approaching or above 65% humidity grows mold and insects love you. Anything below around 15% can make things brittle.I also use these in my clarinet DIY reed cases to keep an eye on the approximate humidity levels. The photo shows a few minutes after I put a wet reed in there. You can see the strip shows purple where it is is closest to the wet reed. This can prolong the reeds life as cane is sensitive to and responds quickly to moisture...too much or not enough.BTW: A roll of this will last a very long time. I have little pieces inside cases, on walls, inside cabinets, by my computer, in my instrument cases, inside archival prints boxes, etc.