Hardened power armor

A suit of T-51b power armor ( which has undergone a special chemical hardening process. The nature of this process is unknown, but the result is greater resistance to all forms of damage. A hardened suit retains the original's bonuses: +3 Strength and +30 Radiation Resistance.

Fallout
Can be hardened in Boneyard by Miles (one suit of power armor and Chemistry journals required).

Fallout 2

 * Crockett, San Francisco, at Hubologists' HQ (2 suits)

Fallout 2
Utwardzony Pancerz Wspomagany Закалённая силовая броня