Fire Extinguisher Pnuematics Adapter
This is a basic cap that adapts a used fire extinguisher to a multi-use pressure vessel for things like drink carbonation, etc. Dry chem fire extinguishers are typically large aluminium tubes that can hold high pressures, this cap is not recommended for anything above 65 PSI.
WARNING: Dry chem extinguishers must be copiously cleaned before use, and cap must be printed with thick walls/solid for pressures above 25 psi.