Increases your Recovery rate from the Blindness, Broken, Exhaustion, Exposed, Haemorrhage, Hindered, and Oblivious Status Effects by 20/25/30 percent.
This effect also applies to all other Survivors within 8 metres of your location and lingers for 15 seconds.

Reduces the volume of Grunts of Pain while in the Injured State by 25/50/75 percent.
Iron Will cannot be used when suffering from Exhaustion, but does not cause the Exhausted Status Effect.

Start the Trial with 3 Tokens:

When a Chest has already been opened, consume 1 Token to rummage through it for an Item.
Rummage through Chests 40/60/80 percent faster.
Rummaging is only available once per Chest.

Reveals the Auras of available Pallets whenever you are in the Dying State.
While being carried by The Killer, reaching 25/20/15 percent Wiggling progression activates Power Struggle:

You can drop a nearby, standing Pallet to stun the Killer and escape their grasp.
Power Struggle deactivates after triggering successfully.

Increases your Altruistic Healing speed by 100 percent for the next 30/60/90 seconds whenever you rescue another Survivor from a Hook.

Each time a Survivor other than yourself is killed or sacrificed, Sole Survivor gains 1 Token, up to a maximum of 3 Tokens:

Each Token grants a stack-able radius of 20/22/24 metres within which the Killer is unable to read your Aura, up to a maximum of 60/66/72 metres.
Once you are the last Survivor standing, you benefit from the following effects:

Increases your Repair speed of Generators by +75 percent.
Increases your Opening speed of the Exit Gates and the Hatch by +50 percent.
Increases the odds of becoming the Killers initial Obsession by +100 percent.

The Killer can only be obsessed with Survivor at a time.