What's the stalk of the twist shower?

The lever for twisting the shower is as follows:

1, unscrew the shower nozzle. If this stalk is used, it means that the shower head may not have water, and then let the shower head be removed to see where it is.

2, that is to say, removing this shower is called unscrewing the shower.

If the shower is broken or there are other problems, it must be repaired before it can be used again.