ProMod Nitrous Solenoids feature a 3-port design - inlet, outlet and purge. The inlet port is 1/4 NPT thread with a coarse screen filter to keep larger debris from entering the solenoid. The inlet port is clearly marked on the solenoid body with a laser etched IN. The .122 orifice outlet port is located on the bottom of the solenoid and has 1/8 NPT threads. The purge port is a straight through design, allowing liquid nitrous to be pulled in to the bowl of the solenoid when the system is purged. It is also 1/8 NPT and is clearly marked on the solenoid body with a laser etched P. We include a 1/8 NPT pipe plug should you decide not to utilize this port and instead mount your purge solenoid using the in-line swivel manifold. Seal all fittings screwed in to the solenoid body using blue thread lock. T6061 Billet Aluminum - That's what the ProMod Nitrous Solenoid Bases are precision CNC machined from. They are then anodized black and laser etched. Next in are the piston, return spring, and steel tower. Because of the aluminum base, we utilize a steel washer to maintain superior magnetics and proper operation. On top of the washer goes the heavy-duty epoxy encapsulated coil. Finally, the matte black powdercoated steel can completes the unit and is topped of with one of our attractive solenoid stickers. 3.5 oz is what you'll save compared to a standard steel body solenoid. That weight saving adds up on direct port systems! The coil draws 27 amps, so we suggest using 10 ga wire for power and ground. Finally, the .122 orifice is capable of flowing up to 500 horsepower!