Power packs (also called power paks or power cells) provided energy for many vehicles, and even small and/or large blaster weapons and tools.
Chewbacca holding a small power cell.
Most power cells contained concentrated amounts of gases that, when heated, formed plasma. In small blasters, power cells were used to create blaster bolts that were not nearly as powerful as blasters using a combination of magazines containing gases (that after being heated would change into plasma) and proper blaster power packs. Power cells were flammable.
Particle power packs, used in the weapons by the Trandoshans, released unstable particles through an electrical exciter coil and were shot out the barrel. Sturm dowels were components.
A small power cell could power a prosthesis without the need for recharging.
The Telgorn Corporation produced power cells.
Certain creatures, such as the shadow lurkers, fed on the energy of power cells, rendering the devices useless.
Power packs were used in starships' cooling units.