3/8" Male NPT x 1/2" Compression Brass Connector This is a 3/8" male NPT by 1/2" compression straight pipe connector. This fitting connects 1/2" OD brass, bronze, copper, steal, aluminum or iron pipe to a 3/8" female NPT outlet or fitting in a straight line. Specifications: Material: Brass Approximate Length (Nut Screwed Down Hand Tight): 1.5" Vibration Resistance: Fair Temperature Range: -65°F to 250°F Use With: Brass, Bronze, Copper, Steel, Aluminum, and Iron Pipe Note: 3/8" NPT measures about 5/8" in diameter.