When base class is Rune Knight: ASPD +2, ATK +15%.
When base level is 175: All Stats +10.
When refine level +10 or higher: All Stats +10.

When equipped with True Seyren Windsor Card:
Adds 3% chance for 6 seconds to possess the user with Seyren Windsor spirit when attacking with physical attacks.
During possession, the user granted with +100 ATK.

[iRO Description]
Class: Card
Compounds On: Garment
If used by Rune Knight,
Atk + 15%
Aspd + 2
If the users base level is 175 or higher,
All Stat + 10
If upgrade level is +10 or higher,
All Stat + 10
Set Bonus
Rune Knight Seyren Card
True Seyren Windsor Card
Adds a 3% chance of buffing the user for 6 seconds when performing a physical attack; Atk + 100.

More Information on Combo:

• Rune Knight Seyren Card & True Seyren Windsor Card