SIZE: 4pcs 5/16 inch barb to 1/8 NPT male thread hose barb fittings. Air hose barb fittings with max working pressure up to 300psi, temperature range of -40°F to +160°F, more durable than iron and steel pipe fittings | PREMIUM QUALITY: Our hose barb fitting is made of CA360 premium forged brass, thicker, stronger and durable. Air hose pipe fitting has accurate, smooth and deep thread, with corrosion resistance, high temperature ductility, low magnetic permeability and long service life | PRECISE THREADS: Hose barb end is tightly connected with hoses, NPT threads are designed with deep and accurate thread to ensure tight and no leak connection and easy installation. Can use teflon tape before installation to further strengthen the seal and prevent air leakage | SPECIFICATIONS: KOOTANS barbed hose fittings meet specifications ASTM B584 and ASME/ANSI B16 for quality assurance. NPT thread size is a nominal pipe size and it does not represent the actual diameter. NPT thread has a 60° taper to ensure stable and firm connection and increase sealing performance | WIDE APPLICTAION: The air hose adapter fittings can be used to connect various hoses, can apply to industrial use, automotive, plumbing pipes, temperature control circuits, pneumatic circuits, vacuum, flfluid systems test apparatus, fuel line, coolant lines, meet a wide range of transportation needs