US Patent 7779844 Self-fitting device for location in an ear canal

Self-fitting device for location in ear canal, including first end portion joined with second end portion. First end portion including first resilient bladder and first chamber of fluid and second end portion including second resilient bladder and second chamber of fluid. The bladders are in communication via the chambers. First bladder is deformable between at-rest position to in-ear position to insertion position such that first bladder has first cross-sectional area in at-rest position, second cross-sectional area in in-ear position and third cross-sectional area in insertion position. First cross-sectional area is greater than second cross-sectional area which is greater than third cross-sectional area. Second bladder is deformable to cause first bladder to be deformed from at-rest position to insertion position before device is located in ear canal.