| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost earplug having superior insertion performance and adhesion performance to the ear canal and having superior sound insulation characteristics. SOLUTION: This earplug having a shaft core whose hardness in the hole axis direction of the external acoustic meatus is set high and hardness in the core diametrical direction of the external acoustic meatus is set low has a superior insertion performance and adhesion performance to the external acoustic meatus bent into a doglegged shape and provides superior sound insulating characteristics. |
