Dlc diamond like coating the main characteristic of the diamond like coating is reduction of abrasive wear besides this its surface hardness is higher than most coatings this ensures a long term function optical stability and higher durability warranty the life of all kmc double x durability and triple x durability chains are guaranteed to last longer than other brands double x durability warranty includes all x sl x el x10e x9e x101 and x1 models if you are not satisfied with the