Superior Fortitude Stim

Superior Fortitude Stims are basic stimpacks.

Use
Upon activation of a Superior Fortitude Stim, a character's Endurance ability is increased by 60 points for the next 60 minutes. Each character can only benefit from a single stimpack at any one time; if a new stimpack is activated before the duration of another has expired, the effect of the previous stimpack will be replaced by the effect of the most recently used item.

Source
Superior Fortitude Stims can be bought from level appropriate stimulant and medical droid vendors. They can also be gathered as random world item drops from level appropriate chests.
 * Vendor store price
 * credits 2,500