Underground space in Shanghai can see your privacy through the x-machine as else where do, in the name of public security guarantee. However it either compulsively cooperated with the general passengers or voluntarily, the screen itself is a beauty documentation of the modern life.
The two cursive calligraphical characters of Chinese is the word of "Safe" or "Secure", it's made by wire-electrode cutted metal plate, sandwiched with two KT boards (25x15cm), passengers are asked to put it inside their handbags or backpacks before the X-ray check machine.