The metal fatigue inducer was a handheld weapon developed by a top-secret lab working for the Venusian Ministry of Defence.
An anti-Dalek weapon, its purpose was to weaken the metal of a Dalek's casing (rendering it susceptible to more conventional means of attacks) by firing penetron rays which randomised the molecular structure of Dalekanium.
Schematics of the silica destructor and metal fatigue inducer were stolen by the Unispace agent EM2 on behalf of Earth. (NOTVALID: Anti-Dalek Weapons)