The present description provides an earplug. One exemplary earplug described herein includes a stem and a sound attenuating body attached to the stem. The sound attenuating body includes a leading end, a base end, a longitudinal axis extending between the leading end and the base end, and a flange extending at least partially over the stem and having an exterior flange surface and an interior flange surface having a plurality of one or both of protrusions or recesses. The earplug further includes a flange cavity including a continuous volume around a perimeter of the stem between the interior flange surface and the stem. A distance between the interior and exterior flange surfaces varies around a perimeter of the flange at a plane intersecting the flange transverse to the longitudinal axis.
