An insert for inclusion in a substantially sealed container to control the relative humidity within the container is provided. The insert is a packet at least part of the surface of which is a membrane capable of passing water vapor and which contains a buffering substance which is a saturated salt solution...http://www.google.com.au/patents/US5037459?utm_source=gb-gplus-sharePatent US5037459 - Device for controlling relative humidity within a substantially sealed container
