Key Features:Dynamic Chain Engagement (DCE) is used to hold the chain and help prevent chain jump out. This is achieved by using a broader and taller tooth profile in conjunction with a special hooked leading edge and alternate profiled tooth shaping. This provides superior chain retention, lower driving sound, increased durability and drag to a minimum,Steel teeth and alloy spider construction for rigidity, lightweight and durability,12-speed chain compatible,Available in 38T/34T,Chain ring fixing lock nut not included,For 53 mm chain line.