Abstract: A hand held, manually operated apparatus for use in applying bursts of air under pressure to the chest wall of a human during chest percussion therapy having a cup shaped outer shell terminating at a lower substantially circular continuous edge and a cup shaped inner shell terminating at a lower substantially circular continuous edge where the outer and the inner shells are joined together at their substantially circular continuous edges to form a substantially flat surface and a sealed chamber between the outer and inner shells. A fluid is located within the sealed chamber between the outer and inner shells, and the inner shell forms an open concave chamber that extends into the inner shell from the substantially circular continuous edge of the inner shell. An elongated handle is removably attached to the closed end of the outer shell.