84-94 Porsche 911 Carrera C2 C4 Intake Mass Air Flow Sensor Adapter Material: High Quality CNC Aluminum Fits on 3 Inch filter ONLY; Cannot be used with STOCK air filter. Easy to install!! Direct Bolt On!! Remark: This mass air flow sensor adapter does NOT include mounting bracket, nuts and bolts. However, most application can reuse the stock bolts and nuts from the stock air box. Vehicle Application: 1984 1985 1986, 1987 1988 1989 1990 1991 1992 1993 1994 Porsche 911 Carrera C2 C4