Belt of Iron Will

 may refer to one of two distinct generic belts in :

Enchantment

 * Fortify Willpower – 10 points for 30 seconds on self

Acquisition
This belt appears exclusively as random loot. There are 125 instances that it can possibly spawn, most notably within chests inside Daedric ruins.

Enchantment

 * Fortify Speed – 5 to 20 points for 30 seconds on self

Acquisition
This belt appears primarily as random loot. There are 125 instances that it can possibly spawn in addition to one static occurrence as part of Unila Berendas' inventory. She resides at the Rethan Manor on the Odai Plateau.

Trivia

 * Based on the second item's ID code, the belt's name was an oversight on the part of developers. It was likely intended to be named Belt of Feet of Notorgo, as per the Feet of Notorgo spell with a similar effect that appears in both and.