Lifegiver or Life Giver is a perk in Fallout, Fallout 2, Fallout Tactics, Fallout 3, Fallout: New Vegas, Fallout 4, and Fallout 76.
Overview
Fallout, Fallout 2 and Fallout Tactics

+4 Hit Points for each rank of this perk per level.
Fallout 3 and Fallout: New Vegas

Gameplay articles: Fallout 3, Fallout: New Vegas
You gain an additional 30 Hit Points.
Fallout 4

Gameplay article: Fallout 4
Gain 20/40/60 extra Hit Points.
Fallout 76

Gameplay article: Fallout 76
Gain a total of 15/30/45 Hit Points to your maximum Health.
Fallout: The Roleplaying Game

Gameplay article: Fallout: The Roleplaying Game
Increased Hit Points.