For quickly and accurately diagnosing fuel pressure problems on GM, Chrysler, Jeep and Ford vehicles with multiport fuel injection systems. Simply fasten adapter to the Schrader valve on the fuel rail. Use the 0-100 PSI gauge (with accuracy within +/-1%) to check for adequate fuel pump pressure, or bleed air from the system with the bleed valve. No. 7430 quick-disconnect 90-degree elbow fitting, and No. 7272 Ford EFI quick-disconnect fitting are also included in this set.