This type of trumpet is in common use,suitable for all kinds of 12V cars,sedan,SUV,and other parts of the motor.
This type of trumpet is double inserting disk,no need for installing the wire harness.
but if your car only have one trumpet,you should install the wire harness.
The outside of the white part is the output wire,red part is the input,black part for cling the iron,blue parts for cling to the positive pole,the middle for open circuit.
Two trumpet make the sound more comfortable,suitable for different people.