| CPC H04R 1/1016 (2013.01) | 18 Claims | 

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               16. An in-ear wearable audio device, comprising: 
            an eartip comprising: 
              a body having first and second ends, an inner wall extending between the first and second ends defining a hollow passage to conduct acoustic energy, and a deformable outer wall connected to the inner wall of the body at the first end and tapering away from the inner wall toward the second end, 
                  wherein the deformable outer wall is functionally graded from the first end to the second end to comply with an entrance of an ear canal of a user, and 
                  a retaining structure coupled with the body, 
                  wherein the inner wall of the body is functionally graded to have a greater stiffness proximate the first end of the body. 
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