The variation of the relative humidity (RH) in an experimental exhibition case containing silica gel buffer has been monitored over a period of 2 1/2 years. Whereas the RH in the room varied between 20% in the winter and 70% in the summer, it remained inside the case within acceptable limits (40-58%). Short time variations were completely eliminated and long time variations were slow and gradual. Our experiment shows that in exhibition case which contains silica gel does not require maintenance for many years in regions with low winter and high summer relative humidity. See also AATA 18-96.