You have futher attuned your essence to a specific subset of veils.
Prerequisites
Veil Set Focus, ability to weave at least 1 veil from a veil set, veilweaving modifier +3.
Benefit
When you gain this feat, choose a single veil set to which you have already applied the Veil Set Focus feat. Add +1 to the Difficulty Class for all saving throws against any effects from the veil set you select. In addition, all veils from the chosen set gain +3 to their hardness while woven. The bonuses from this feat stack with the bonuses from Veil Set Focus.
Special
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new veil set to which you already have applied the Veil Set Focus feat.