This type of capacitor appears to be the primary power source for the petrusite drills which supply power to the MSU. The petrusite capacitor is also used as a backup power supply on Helghast air assault craft, as well as on Overlord Dropships. The capacitor can also be used to provide a power supply for doors if their main power supply is disabled or cut off. Despite the Helghan origin of petrusite, the petrusite capacitor can also used on ISA intruders.