For 1999-2004 Mustang 4.6L with a non-return style fuel rail, installation is simple with the CNC-machined billet adapter in these gauge kits. It has two pressure ports for gauge(s) and/or fuel to supplement nitrous. The liquid-filled fuel pressure gauge is available with a black, silver (machined), carbon fiber-look, or white face. Kits also include dual O-rings for positive sealing, a plug for the second fitting (should nitrous or a remote gauge be added later), and mounting hardware.