The lower valve core performs a switching function.

下阀芯起开关作用。

youdao

It can not only be of direct switching function, but self-locking switching function.

它既可以具有直接的切换功能，也可以具有自锁切换功能。

youdao

It can not only be of direct switching function, but self-locking switching function.

它既可以具有直接的切换功能，也可以具有自锁切换功能。

youdao