Proper fuel pressure is critical for adjusting your carburetor or fuel injection, so don't rely on a poor quality gauge - get a Big End Performance direct mount fuel pressure gauge. Our 1-1/2 in. diameter Comp White series gauges have a white face with bright red pointer and black numbers for easy reading. They are liquid-filled for accurate, steady readings. Gauges have a 1/8 in. NPT center back male fitting.