The VP-40 regulating pump is capable of performing like no other fuel delivery system. It delivers an ideal .25 PSI to any model carburetor from a .15 to a 3.0 cu.in. engine. The pressure remains constant throughout the entire speed range, making the carburetor adjustment easy and simple. Once the needle valve is adjusted, the mixture will not vary regardless of how low the fuel or the attitude of the airplane, thus eliminating rich/lean runs altogether. that it is designed for smoke, gas and diesel fuels. Pump installation is simply a matter of drilling and tapping a 6/32 inch hole in the backplate or mounting lug, installing the pressure fitting (supplied), attaching the impulse line (supplied) and mounting the pump. Specs: Diameter: 1" Length: 1.5" Weight: 23 Grams Flow Rate: 3.5 Oz./Minute