The armored MET-CDS Curtain Door Switch from TANE ALARM PRODUCTS, featuring a reversible mounting assembly,a 36” armored cable and a 3.15” GAP, is designed for installations on tractor trailer roll up doors, providing security and protection for cargo, equipment and personnel, often exposed to security threats in less than ideal locations. Learn more at http://www.tanealarm.com/products/commercial-contacts/met-cds.