MRP SXg Carbon Chain Guide 34-38T ISCG-05, Black Compatible with chainlines 50mm and wider, including Boost 148 Swingset hardware allows guides to rotate apart for easy chain installation Compatible with 1x7, 1x9, 1x10, and 1x11 drivetrains Full-sized upper and lower guides with quiet, TPU co-molded inner Thick carbon backplate for improved stiffness, weight, and durability