the water in the form of vapor in the free volume of the enclosure will be in equilibrium with water absorbed by the polyimide the absorption and desorption is completely reversible and the polyimide content of the connector will generally be sufficient to control the relative humidity over the indicated temperature range if it is not then wires 30 extending internally within dasd 10 between connector 26 and the components therein may be insulated with a polyimide which will also absorb and desorb water and together with that of connector 26 will absorb and desorb the required amount of water to maintain the relative humidity this will be accomplished without any adverse effects on the insulating properties of wires 30 for example for 2 milligrams of water it has been determined that the required volume of polyimide is approximately 0 10 cc this volume of polyimide can be achieved by using a film thickness and film area corresponding to the values in table 1 table 1______________________________________kapton thickness film area______________________________________2 mil 18 8 cm sup 23 mil 12 5 cm sup 25 mil 7 5 cm sup 2______________________________________ referring to fig2 as an alternative the polyimide film 32 having the thickness and film area specified in table 1 can simply be placed on an internal surface or surfaces of dasd 10a in an unobtrusive position the.