Easton's direct-mount monotubes use a new narrow/wide design specifically adapted to road and gravel applications. The tooth profiling is modified into a multi-directional design with the intention of creating a positive chain roller engagement. This in turn helps to prevent the chain from falling off in difficult terrain. Optimized for 11-speed drivetrains, although it is compatible with 9, 10-speed chains as well as Sram Eagle and Campagnolo 12-speed groupsets. Not compatible with Flattop AXS or 13 Speed Campagnolo kits. SINGLE DIRECT MOUNT: 38T, 40T, 42T, 44T, 46T, 48T, 50T MATERIAL: EA90 ALUMINIUM