If your horn fails due to any cause during the first year, you must return the item to the vendor at your own expense for testing and verification of the alleged defect. If the defect is verified by our technician, and you enclose a receipt from the carrier (USPS or UPS), we will ship you a new horn and reimburse your shipping expense up to $10USD. If the horn fails within 18 months, buyer will be responsible for shipping to repair facility, and if a defect is verified, a flat shipping fee for standard shipping (3-7 days) of $10 for the replacement horn. If the horn becomes defective in 18-24 months. buyer will be responsible for return shipping and a flat fee of $30 for replacement including shipping in the US48. NOTE: The original relay must be returned with the horn for testing. To download a a BETA COPY of our Installation Guide, copy and paste this link into your browser: https://www.dropbox.com/s/5sspf8vhm3qrpt5/General%20Instructions%20for%20Installing%20MARCO%20Tornado%20or%20Hurricane.docx?dl=0