The AFI Dual Trumpet Horn on my nearly 4 year old boat was not working about a month ago. I contacted Marinco, the maker of the AFI horn, via email. After following their techy's suggestions for isolating the problem, it became clear the unit was defective. I contacted Marinco back and they advised me to ship the unit back to them. Yesterday I received a new one in the mail from them. The unit has a 5 year warranty with "free" replacement. I didn't expect to receive a free replacement when I contacted them. They made that fact known to me in the email correspondence. THANKS MARINCO!!!