Force Field
Prerequisites: Barrier, Defend, Energy Shield/Deflection, or Telekinesis
Choose a character without a power that reduces damage.

The character gains Toughness.

The character with this feat can gives Toughness to any character (friend or foe), or just to him/herself?

The feat does not say that the character to which you assigned the feat can choose another character so only the character to which you assigned the feat to can use the feat.

Players' Guide
The character that meets the prerequisites and is assigned the feat is the one that can use Toughness.

Hate to dig out an old thread. Do they only get toughness when they have one of the prereqs on their dial? So if they only have TK on the first 2 clicks they only get toughness on the first 2 clicks as well?

They can use Toughness as long as they have the powers required by the prerequisite and no damage reducers.

They don't need to have no damage reducers throughout their whole dial, so long as they meet the requirements when they are using the feat.

Totally makes sense. Thanks!