Article Reinforcement:

It can be used to upgrade your items... The maximum level that can be reached is level 241.

The requirement for your item to be evolved is that it must be GRADE 10.

Article Reinforcement is 100%, meaning it does not fail.

After evolving the item, it will return to GRADE 1.

You will need to use Yellow Drop to raise its Grade again to Level 10, thus allowing you to evolve it again.

These are the item Level Grades.

Low level items > up to Horus.

Advanced Class 1
Advanced Class 11
Advanced Class 21
Advanced Class 31
Advanced Class 41
Advanced Class 51
Advanced Class 61
Advanced Class 71
Advanced Class 81
Advanced Class 91

Article Reinforcement can be obtained from NPCs in the City of each Race.