STAINLESS STEEL Fuel line for a dual inlet Holley 4150 double pump and vacuum secondary with 2 metering blocks. Inlet measures 9 5/16″ center to center. High quality dual feed fuel lines are made of 3/8″ 304 stainless steel tubing. The fuel lines are Electro Polished for a High Luster. The end fittings are made of 303 stainless steel and are silver brazed to the tubes. These are manufactured here in the U.S. by Graham Performance Tubing. The second picture displays the end of the line that you will connect fuel supply to. HOSE – Male hose barb for 3/8″ rubber hose.