Interstate Pneumatics FPC660 Brass Female Coupling Adapter 3/8 Inch x 3/8 Inch NPT Female Threads: 3/8 inch x 3/8 inch NPT Female - Machined (Provides seal tight threads) Temperature Range: -65 F to 250 F Maximum Operating Pressure: 250 PSI Conformance: ASME, SAE, NPT Material: Brass - Excellent strength and ductility, corrosion resistance, low magnetic permeability