Ironwall/Release Jewel 4

Slot size4
RarityRarity 11
SkillGuard+1 level
SkillFree Elem/Ammo Up+1 level

Skills

SkillLevelEffect
Guard1Very slightly decreases the impact of attacks.
Free Elem/Ammo Up1Draws out 33% of hidden element and expands clip size for some ammo.

How to get it

FeystoneChance for a rarity 11 decoration
Carved Feystone37%
Sealed Feystone55%

Decorations come from Feystones (and Melding). The chance is for any decoration of this rarity; the exact jewel inside that rarity is then rolled.

Data: Monster Hunter World: Iceborne game files (final version 15.11).