forgot to mention.......... the electronic blow off is very simple to install.... at the back of the box there is wiring diagram show how to install the blow off....... the item in the box is battery, wire, amp, remote and speaker.... u can control the sound with the remote or if u have tachometer with shift light u can control it with the shift light... when the shift light is on the speaker will sound... if u want to make the sound louder u can add more speaker... as much as u like....