Aeroquip Fitting Perm Thermo SAE 37

Carbon steel fittings without any coating tend to rust out pretty fast in wet or dirty environments, but the Dura-Kote plating on this one is specifically there to fight that. It gives the fitting a solid layer of corrosion resistance, which matters a lot when you're running hose assemblies somewhere they're gonna see moisture, grime, or general abuse on a regular basis. It's one of the reasons this fitting gets used in demanding industrial setups where downtime from a corroded connection just isn't acceptable.

It matches a -4 line, hose, or tube on one side and a JIC 37 degree female connection on the other. The JIC end is listed at 0.4375 inch, so it is meant to land on that size JIC 37 connection.

Dura-Kote plating gives it some serious corrosion resistance. It should hold up pretty well even in tougher environments.