Multi-time insertion delay devices were designed, and the metallic delay cord was used in the delay element.

设计了多种时间装定延期体，单元延期体采用金属延期索。

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Multi-time insertion delay devices were designed, and the metallic delay cord was used in the delay element.

设计了多种时间装定延期体，单元延期体采用金属延期索。

youdao