X-9 manganese,pair of snow chains, 9 mm slim fit cable links Specific for cars with limited gap between tire and mechanical parts Manganese steel for extra wear and tear resistance. Self-tensioning system. After the installation and the first manual tensioning, the chains tighten automatically while driving. No more stops for tensioning. Automatic release function. New trigger mechanism for a quick and easy release Approved TÜV AUSTRIA - ÖNORM V 5117 GEPRÜFT