US Patent 7931027 Earplug with engagement means

An earplug for a hearing aid adapted for engagement with earpieces made of materials with a comparatively high hardness. The earplug comprises a resilient sleeve and a shell, the shell having an outer portion adapted to fit within a user's ear canal and a central bore, the central bore having a first abutment shoulder adapted for retaining the resilient sleeve inside the shell and a second abutment shoulder adapted for providing a stop for the resilient sleeve and for the earpiece. Hereby the resilient sleeve is able to combine relatively relaxed manufacturing tolerances with precise positioning of the earpiece inside the earplug.