This offer includes all trays ROTOR when you purchase Q RINGS oval or round, direct or star mount, 1x or 2x. Buy any tray ROTOR and get the second item of equal or lesser value at 50% off. We have used all our experience in developing oval Q RINGS to produce an innovative round tray solution. CNC machined from ultra-lightweight 7055 aircraft grade aluminum, our new 4 arm chainrings are compatible with our lightweight ALDHU crankset as well as all Shimano® cranksets. 4 bolts. Combined with our new ALDHU chainring and crankset, the smart splined interface between the axle and chainring provides a robust and smooth engagement that allows you to maximize the efficiency of power transmission in your pedal rotation.Specifications:Weight: 133g for a 52/36