The Juggernog perk really gives you chainmail armour.
Juggernog is a Perk-A-Cola wich gives you armor.
It is a very useful perk,which gives you more health,allowing you to survive hordes of zombies.
It is the cheapest perk in game,costing 2500 points,so its worth it.
Trivia
-The Juggernog really gives you Chianmail Armour (Open your inventory and go over the armour with your mouse)