Extend Supernatural Ability

(Tome of Magic, page 73, DnD 3.5)

[General]

You can cause a supernatural ability with a duration to last longer than norma 1.

Prerequisite

4 HD, supernatural ability

Benefit

Once per day, you can extend a supernatural ability that has a duration. When you use an extended supernatural ability, it lasts twice as long as normal. A supernatural ability that has a duration of concentration, that happens instantaneously, or that permanently affects a target is not affected by this feat. You must declare the use of this feat before you use the ability. Extending a supernatural ability does not require a separate action.

Special

This feat can be taken multiple times. Each time it is taken, you can extend a supernatural ability one additional time per day. You cannot extend a particular use of a supernatural ability more than once.