This "atomizer" nozzle can be used in either the cockpit or the engine bay. It is designed to aerate the AFFF solution, turning it into foam. It will not work with older Halon fire suppression systems.
SPA Design nozzles have a push-in connector designed for use with 1/4" Dekabon Tubing (Part No. 2456-.250). They will not work properly with bare aluminum tubing.