Atom's Bulwark

Atom's Bulwark is a unique piece of armor in the Fallout 4 add-on Far Harbor. It is a legendary arm or chest piece of Marine armor.

Characteristics
It provides a Damage Resistance and Energy Resistance of 15 at 0 Rads, equal to combat armor. They both increase linearly according to the following: every time your current radiation level increases past a 10% threshold of your total health, your total DR and ER will both increase by 5. Specifically, if 10% of your health bar is taken by radiation, you will gain 5 DR and ER. If 90% of your health bar is taken by radiation, you will gain 45 DR and ER.

If you are below level 40 it will spawn as right or left arm while if above, a chest piece.

Location
Rewarded by visiting High Confessor Tektus after completing Reformation or after destroying Far Harbor in Cleansing the Land.