ERA

Explosive Reactive Armour. Currently called "ERA Armour" in-game. There is a sloped variant that accomplishes the same function for 2.5 material, but is non-structural, receiving no bonus from armour placed behind it.

Usage
ERA is used mostly to counter HESH and HEAT. It is used up completely whenever activated. HESH triggering on external ERA is nullified entirely, and internal ERA can be used to either "catch" fragments, or reduce their AP (as ERA has only 3 AC). A HEAT-beam passing through ERA is also nullified. Frags (be it from missiles, frag shells, HESH, HEAT, or CRAMs) will be removed if too close to activating ERA (as will any shell, although this is less likely and depends on the game's speed), and HE triggering on ERA is greatly reduced in strength.

External ERA can be stripped quite fast with airburst frag or airburst HE rounds.