LG G5300 Manual De Usuario página 127

The PUK2 code, supplied with some SIM cards, is required to
change a blocked PIN2 code. If you lose the code, also contact your
service provider.
The security code protects the unauthorised use of your phone. It is
usually supplied with the phone. This code is required to delete all
phone entries and to activate "Reset settings" menu. The default
number is .
25