| 摘要 |
An earplug of the slow recovery type is described, which has open cells for expelling gas to the outside during compression, but which resists the entry of water through the outside and the soiling of the outside by dirt. The earplug includes a body formed of pressure-molded slow recovery resilient foam material forming multiple gas-filled shells. The plug body has a surface region forming a skin wherein the average cell cross-sectional area is less than half that of cells at the center of the body, and is less than one-tenth millimeter, the surface region being primarily continuous.
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