Sharing some photos of my Hella SuperTone installation work:
Mounting the twin-tone horns (one low tone, one high tone) on a mounting rail (the rail came from my mechanic who happened to have a spare). I wanted to space the horns apart, by at least 2-3 feet between them, so the sound is clear:
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After measuring off, mount the horns on the rail and secure tightly:
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Forgot to snap a photo post-install, but here's my horns when I did it myself (without a proper mounting rail that you see above). After I tested out this install, found out it's not as loud as it should be, so drove to my mechanic and ask him re-do (mount on bracket + rewire using thicker wire + add 1 more relay):
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VERY satisfied w/my horns now. Sound comes out clearly... just behind the center grille (can see the horns if you squat down in front of H emblem).
Am going to enjoy these horns for a long looooong time

Hey actually I prefer your installation, neater without the rail. Its the 30A relay that produce the 118db. The stock not enough juice to give these Supertone the boost.