What does the sign on the mobile phone charger mean?

On the side of the charging plug of the mobile phone charger, the parameters of the charger are always printed. For example, there is a sign printed with "small house", which means "indoor use only", if it is used in a non-indoor environment, it may cause harm.

The icon printed with "back" means "double insulation".

There is a mark with "3 Cs inside the oval", which means that this charger complies with the "3C safety certification". What does 3C mean? You can check it online. In fact, just remember that it refers to my country's compulsory product certification system, which is the most basic safety certification.

The "10 or 20" icon printed in the circle with arrow means that the charger "can be recycled" for 10 or 20 years.

If there is "Latin numbers and letters in the circle", such as V, VI, this is the "energy efficiency certification" mark, "V" represents energy efficiency level 5, and "VI" represents energy efficiency level 6.