You can check out game guide on 12SKYM-Reborn

● Overview
ㆍAdditional bonus stats are provided based on the enchant level of the equipped armor (armor/gloves/boots).
ㆍSet effects are applied when wearing GOD-grade armor.
● Set Effect Activation Conditions and Options
ㆍThe set effect applies even when mixing 1st to 4th GOD-grade armor pieces.
ㆍIf the enhancement levels differ, the effect will be based on the lowest enhancement level among equipped pieces.
:: Ex) Wearing Armor +20 / Gloves +20 / Boots +18 will activate the Stage 2 Set Effect.
ㆍEach stage provides a unique visual set effect.
ㆍWhen all armor pieces are 3rd GOD-grade armor enhanced to +20, a special set effect will be activated.