This 12V starter relay solenoid is designed as a replacement for systems originally equipped with part numbers B6AZ-11450-A, B-6A-11450A, C6AF, C7AF, C9AF, SS588, or F496.It operates in 12-volt direct-current electrical systems and features a 4-terminal configuration with a grounded base, motor terminal (5/16-24), switch terminal (5/16-24), and relay terminal (10-32 post).Compatible with a range of starters including models 3115, 3117, 3123, 3124, 3128, and others as listed.Also replaces additional OEM and aftermarket part numbers.Fits select vehicle models including Aerostar (1986–1991) and Bronco (1965–1991) with specified engine types.