Traditional Culture Encyclopedia - Hotel franchise - What's this switch in front of the hotel?

What's this switch in front of the hotel?

When you pull the black plastic part, will the two spike clips turn out? If it is, then this is the buckle that hides the anti-theft chain. There should be a box with a chain or a lock tongue embedded in the door, which can be seen after opening the door.

You can find it by searching for "hidden anti-theft chain" in Taobao.