Inverted flare union tees are used on hydraulic brake, transmission and fuel lines as well as LP gas lines to connect three tubes together. All three sides of the fitting feature female inverted flare pipe for joining tubing together. The internal inverted flare creates a strong metal to metal seal. They are made of brass for high corrosion resistance and can withstand up to 2,800 PSI. Used on copper, brass and steel tubing.