| 摘要 |
The hearing protector comprises a tubular ear plug (2) with a central channel (4) within whose outer end (5) fits the housing (6) for a muffling control (7). The base of the housing (11) only partly blocks the central channel, leaving an aperture (18). The muffling control can rotate to a number of discrete positions within, but is retained by, the housing; its base (13) is pierced by two or more holes (15).
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