This cable is an amplifier bypass cable ( it allows you to drive the cars speakers directly from your new head-unit bypassing the cars old factory amplifier.
To find the amplifier location trace back the Data (computer type connector) from the radio to the amp location.
on some cars this is under the drivers seat and on others its underneath the centre console below the original head-unit.
Car models: The years stated refer to the model's years of manufacture, please check the item description for information about any changes there may be within these productions years.
Ford - Cougar (1998 - 2002)
Ford - Explorer (1997 - 2001)
Ford - Fiesta Mk5 (1999 - 2002 )
Ford - Focus Mk1 (1998 - 2004 )
Ford - Puma (1997 - 2002 )
Ford - Ranger (1999 - 2006)