Invest Life Energy
Whenever a character with an item familiar gains hit points from levelling up, he may choose to put some or all of those hit points into his item familiar. He intead assigns the hit points to the item familiar's hit point total. For every 3 hit points he assigns to the item familiar, he gains a +1 bonus that he can apply to either his Fortitude, Reflex, or Will save. He can apply multiple bonuses to the same saving throw, but he may not have more points of bonus to a saving throw than his base save modifier for that saving throw. The choice of where and how those bonuses are applied can be changed once when gaining a new level.
If the character loses the item familiar, is separated from it for one day per level (see the Item Familiar feat description), or if the item familiar is destroyed, these hit points and the bonuses related to them are lost.
For example, Jannilus has just achieved 4th character level, and he takes a level of wizard. He gains 5 hit points this level, and assigns 3 hit points to his item familiar. His item familiar's hit points increase by 3, and Jannilus's hit points increase only by 2. Jannilus now gains a +1 bonus that he decides to assign to his Fortitude save. When he reaches 5th level and choose another level of wizard, he assigns 3 hit points to his item familiar and gains another +1 bonus. However, he cannot assign it to his Fortitude save, because his base Fortitude save modifier is +1.