Abstract: Occlusion devices, earpiece devices and methods of forming occlusion devices are provided. An occlusion device is configured to occlude an ear canal. The occlusion device includes an insertion element and at least one expandable element disposed on the insertion element. The expandable element is configured to receive a medium via the insertion element and is configured to expand, responsive to the medium, to contact the ear canal. Physical parameters of the occlusion device are selected to produce a predetermined sound attenuation characteristic over a frequency band, such that sound is attenuated more in a first frequency range of the frequency band than in a second frequency range of the frequency band.