The ETCL-9 operates by projecting a focused column of electrothermal plasma into an enclosed or semi-enclosed space — a room, a vehicle interior, a corridor — and then triggering a rapid compression wave by collapsing the plasma column's magnetic containment field in a controlled sequence. The result is a brief, violent atmospheric compression event within the target space: a pressure spike lasting approximately 80 milliseconds that is sufficient to rupture eardrums, cause pulmonary barotrauma, and collapse unsupported structural cavities. The plasma itself is secondary — it is the compression wave that constitutes the primary weapon effect. Living targets within the affected space experience the sensation of the air being forcibly removed from their lungs, which is where the nickname 'Ironlung' originates.

Ringo Corponation developed the ETCL-9 in response to a specific tactical problem: neutralizing threats inside armored vehicles and fortified rooms without destroying the structure itself. The weapon is fired at a surface — a wall, a door, a vehicle hull — and the plasma column penetrates through gaps, ventilation openings, or thin materials before the compression event occurs inside. The outer structure remains largely intact while the interior is devastated. This made the ETCL-9 extremely valuable for operations where the goal is to secure a location while preserving its contents, and correspondingly attractive to actors who do not want the evidence of what was inside destroyed.

The weapon is large and unwieldy, requiring a shoulder brace for stable operation. Its barrel is unusually long for an energy weapon — 94cm — because the plasma column requires distance to achieve the coherence necessary for effective penetration. Operators describe the firing experience as violent: the recoil from plasma projection is substantial, and the compression event produces a concussive wave that can affect the operator if they are too close to the target surface.