When in use, the glass will break if the cover is rotated 90 degrees and the window is smashed. Not only that, the red window breaker, which is only the size of a fist, doesn't need much power to hit it. It can be used by both old people and children in emergencies. At present, the bus safety hammer used is easy to throw away, and it is not easy to break the glass at the critical moment. Recently, the bus safety window breaker, with a clap of the palm of the hand within a second glass is broken, simple and practical, is popular with netizens.