Boveda uses a patented 2-way humidity control that continually responds to ambient conditions by adding or removing moisture to affect the enclosed environment.
It’s well known in science that certain salts mixed with water will naturally regulate humidity. Boveda just patented the way that made it practical for packaging. Other packaging inserts either add moisture or remove moisture. These do both, monitoring the RH inside the container and regulating to the specific RH engineered into the pack.
The packs do not need to be activated or maintained. Once the pack becomes rigid, it’s out of water and needs to be replaced. This could mean weeks to years, depending on the package or container, how much the container is opened/closed and the ambient environment. It’s really that simple, and why we use Boveda in our own humidors.