Each Light Armor shield pick-up restores 50 armor points, increasing it up to but not beyond your max armor. You can often find a few of these throughout the arena, where they can provide you a good boost to get back into the action when low.
Vital Stats

Bonus / Amount | 50 AP |
Initial Spawn | Match Start |
Respawn Time | 30 sec |
Visual Timer | True, in Unranked |
Has Floor Marker | False |
First Appearance | Quake 1 |