pf2e.fyi
From Pathfinder #153: Life's Long Shadows, which isn't enabled.

Iron Lung

FEAT 14
Archetype Golem Grafter

Your lungs are infused with the resilience of iron. Treat the result of your save against an inhaled poison as one degree of success better than you rolled. Additionally, you gain the Exhale Poison ability.

Pathfinder #153: Life's Long ShadowsOGL