The Shimano SLX FC-M7130-1 1x12 crankarms features an entirely new construction, using direct mount chainrings, special gear tooth profile for improved chain retention, and a 181mm Q-factor. New construction provide consistent long-life shifting performance and chain management, and the FC-M7130 crankarms can run 30T, 32T, or 34T, Shimano Direct Mount chainrings on its 181mm Q-factor crankarms, saving weight through the targeted application of hollow bonded construction. Chain Ring Installation tool TL-FC41, Not Included.