Maglite’s used(?) to be the king of flashlights ... So [Travis] decided to upgrade it to make use of the ever-so-common, 18650 lithium-ion battery. Not looking to purchase any components ...

A Maglite was chosen due to its high durability, and easy access to the internals. A schrader valve sticks out of the battery cap, which allows the gun to be charged using a standard fitting.