I mounted them up under the truck, I have the air tank, Viair 450C compressor and an air line running to the rear of the truck, I will install a larger air tank, may not need it, but the Viair is a Hoss, 100% duty cycle. I installed a small Ball valve to isolate the rear air line from the air horn.
Installed them after the first trip through Texas, NOW people see me, (or hear me) when merging into my lane. My button is a foot actuated one, so I can keep my hands on the wheel.
I even mounted Sue another button for her to use if she wants to get someones attention. I think they are around 130 DB.
The last picture shows the air chuck at the back of the truck, that cable hanging down is my rear camera connection for the Monte. I have weather caps I keep on the chuck and the cable connector.
Ozz
http://i7.tinypic.com/24zm74o.jpg
http://i7.tinypic.com/24zvi3t.jpg
http://i7.tinypic.com/24zvl83.jpg
http://i8.tinypic.com/24zvsbd.jpg
'07 3400RL 2nd RTU
2 Golf Cart batteries 3,000 watt inverter, automatic transfer switch
Honda 2000 Generator, Maytag's with 220 Dryer
Stationary domed Sat. dish, LCD 12 Volt Amp gauge, LCD Tank Monitor
3 added 120 volt outlets, On Board Air; 12 Volt Viair 450C compressor
2006 Ford PSD 4x4 Off Road Lariat, Hadley Air Horns, Truck inverter with 110 volts: laptop, Color Backup Camera, Awning lock