When used in combination with an moisture and airtight container, such as a sealed glass canning jar, these desiccant packs are used to protect seeds from moisture. They measure about 3-inches x 3-inches x 1/4-inch. Each pack will protect 715 cubic inches or 0.42 cubic feet or 3.2 gallons.
The packets contain activated clay which is non-corrosive and non-toxic. Absorbs up to 20% of its weight in water vapor in six hours. Not that it really is important to our application, but these bags do meet "MIL SPEC MIL-D-3464E TYPE I and II. QPL certified. ISO 9001."
They can be reused! To reactivate them, start with a room temperature oven (77-85ºF) and slowly increase to 245ºF. Bake them at 245ºF for 24 hours.
for a copy of the Material Safety Data Sheet (MSDS).