Sram pc x01 eagle 12 speed chainit might look normal from the outside but the engineering inside this incredible new chain design that makes possible a gear range previously found only in 2 chainring drivetrains and its also the biggest contributor to the eagle drivetrains ultra smooth precise durable and quiet performance the eagle chains links have a smooth radius with no sharp edges or chamfers which yield a significant reduction in noise friction and wear on chainrings and casse