Armored walkers are a special type of walkers which still carry their body armor and helmets around.
Because of that, they are Bullet Proof. It means that there is a very high chance your ranged attack against them will result in a Body Shot, no matter which level they are. These walkers are marked with a police shield sign.
Armored walkers have more health compared to normal walkers, so combined with their high resistance to ranged weapons, they are a very tough enemy for any ranged class. It is recommended to fight armored walkers with melee classes (Scouts, Bruisers, and Warriors).