From Quake Wiki
This is the best armor in the game. It absorbs about 4/5 of the damage you receive. You get 200 points of red armor, but they will disappear fairly quickly.
|Items in Quake|
|Health | Ammo Boxes | Mega-Health | Quad Damage | Biosuit | Pentagram of Protection | Ring of Shadows | Green Armor | Yellow Armor | Red Armor|