I have the 6" version on my truck, I looked for a good while and found one on eBay for about 1/3 what they want from FS. There are a couple places out there that sell them cheaper as well if you search around.
It's loud enough to get attention, dings every 1/4 turn. You'll notice the balls clack when you're driving around at lower speeds. It was easy to put on too, the brackets center the bell on the hub.
The down side is if you have to pull the wheel/s off you have to dismount the whole setup first.

1956 GMC 370 dump " 'Tater "
1970 VW Volksrod "the Black Bomber"
2007 Chevy Avalanche
2020 Jeep Cherokee Trailhawk,
2005 Harley Davidson FLHTCUI

I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P