0: No protection

     1: Drops of water into the shell have no effect

     2: When the shell is tilted to 15 degrees, the water droplets have no effect on the shell

     3: Water or rainwater from 60 degrees to the shell has no effect

     4: The liquid is splashed from any direction to the shell without any damage effect

     5: Rinse with water without any damage

     6: Can be used in the environment in the cabin

     7: It can be soaked in water in a short time (1m)

     8: Soak water for a long time under a certain pressure