Gonna assume it's a bunch of Amistr Bags that were released on kRO earlier this year.
Each one does:
+1 All stats.
Per 2 Refines: +1% EXP from Monsters, +1% Item Drop Rate.
When +9: Regen 3 SP when a monster is killed by a physical or magical attack.
When +12: Skill casting cannot be interrupted.
But on top of that, one of the bag types offers one of the following skills:
Increase Agility Lv1
Magnum Break Lv1
Improve Concentration Lv1
Outside the +5% elemental resistance and Drop % i dont see any chance to change my FAWs for that bag :/