C339 Is this thing really that useful

Room 305, third floor.

Huang Xing knocked on the door, which had not heard for a long time: Who is it?

Huang Xing replied: I, Huang Xing.

The door was opened after a series of hurried footsteps.

What entered his eyes was the simple and unadorned Zhao Xiaoran. She was dressed in a fairly simple suit, black work trousers, a black sweater, and disposable slippers provided by the hotel