E thirteen direct mount guidering m chainring ethirteen guidering m chainrings boast a revoluntionary dual width tooth design to help keep your chain locked on your ring and not dropped on the trail vital mtb 45 star rating features maximum tooth width and height to engage the chain securely you can pedal through the rough stuff without fear precision tooth chamfers faciltate chain engagement even at extreme chain angles your chain will stay put no matter what gear you are pushing long