Microfusion cell

s are a type of ammunition found in the Fallout Series.

Background
Microfusion cells are medium sized energy production units, described as a "self-contained fusion plant." They were invented in 2066 by U.S. scientists as a potential solution to the energy crisis amid the Resource Wars. Microfusion cells utilize hydrogen isotopes that undergo fusion when subject to heat and pressure. Microfusion cells are labeled with warnings that they may explode if disposed of in fire, and that they have a capacity of "1040.8 VDC." 