+5 stone codes may not be supported on your server and may have become a bug, you can determine the level yourself by playing with the last numbers.

Stone that protects from warrior: 28633
Stone that protects from Ninja: 28634
Stone that protects from Sura: 28635
Stone that protects
from Shaman: 28636 Stone that protects from Monster: 28637 Stone of Cunning: 28639 Stone of
Magic : 28642 Stone of Life : 28641 Stone of Protection : 28638 Deadly Blow Stone: 28631 Grip Stone: 28630 Speed ​​Stone: 28643