Pressure decating is used to set wool and wool blend fabrics. The degree of set and therefore the mechanical properties depend on such variables as moisture content in the wrapper. Mositure content in the wrapper frequently varies from that of the fabric. Moisture can diffuse from the wrapper to the fabric, or vice versa, and change the initial fabric regain. The wrapper is either cotton or cotton and polyester. An experiment to measure the contribution of wrapper moisture content to that of the fabric during pressure decating was conducted. The experiment demonstrate that extensibility and shear properties can be significantly affected by moisture transferred from the wrapper to the fabric. 10 refs.