The only truly bulletproof armor that exists.

The Storm Elite armor was originally a super special armor designed during WW1. An early prototype can be seen in BattlefIeld 1.
A later bulkier and protective version was designed in 1918 and could have possibly turned the tide of the war if deployed properly.

During WW2 miners of the third reich were sent into deep earth to excavate diamonds to be used for the armor.
However the war ended before any suits could be produced.

In 1947 the Storm Elite was finally made a reality. The armor was made of a special "Compressed Diamond-Steel" that was discovered to be completely indestructible. The armor was supported by an exosuit.
The soldier wearing the suit would be armed with the MG-47 Light Machine Assault Gun, which was a modified MG42.
A somewhat identical yet far underpowered example is given a role in Medal of Honor: Airborne.

During the 1950's a lighter version was introduced that traded max protection for agility and a lighter load.

During the 70's a new version was introduced that incorporated special technology into it's headset, including night and thermal vision.
These suits are the inspirations for the armor in the Kerberos Saga.