An earplug including a foam body and a detectable insert completely encased by
the foam body. The earplug is manufactured by forming a channel in the foam body
and placing the detectable insert in the channel. The channel is formed by deforming
the foam body using a punch. The foam body is made from a slow recovery foam which
returns to its original shape thereby encapsulating the detectable insert within
the foam body. In an alternative embodiment, the insert is projected into the foam
body and the foam body recovers to encapsulate the insert.
