The Mark 4 decoy was a single-use deployable anti-plasma countermeasure, first used by the United Nations Space Command Navy during the later years of the Remnant War. The decoy consisted of an unguided, roughly cylindrical prefragmented steel canister, shaped to reduce radar cross-section, containing a central 450 kilogram warhead and a torus-shaped capsule. The decoy was magnetically ejected from the AN/SLE-311 decoy launcher, directed towards incoming guided plasma bolts, or 'torpedoes'. The decoy was remote-detonated with a backup proximity detonation fuze, optimally within 500 metres of the target torpedo. The detonation would destroy the internal capsule and explosively disperse its contents, a 'dust' composed of carbon nanosphere particles, upon which the torpedo would prematurely d