This horn comes with all mounting hardware (including a Thompson Automotive custom designed mounting bracket), a fuse upgrade and full installation instructions. The horn assembly mounts right where your stock horn mounts and uses the same connector. So it is literally "plug & play"
NOTE: This horn is being re-designed by the manufacturer. They are adding more waterproofing. Anticipated availability is March of 2013. Pricing is To Be Determined, but will likely be about 2X the standard Nautilus horn.
Please be certain to select the model year of your car from the drop-down list when ordering. If ordering two or more horns for different generations of car please use the comments section to clarify.