When it comes to nozzle plumbing, the hardline can either be steel or aluminum. You simply cut and flare the tubing to mate to the AN fittings and you're done. Note that the discharge nozzles are designed so that each has three outlets. This means a fan spray of sorts is used to spread the fire-extinguishing agent. Keep this in mind when mounting the nozzles. And also keep in mind that the compressed agent can be dry ice cold. As a result, careful placement in the interior is rather important (don't aim it directly at you or your passenger).