SRAM RED X-Sync Chainring - 40t, 12/13-Speed, 8-Bolt Direct Mount, 6.5mm Offset, Black/Silver, E1SRAM's light, stiff, and durable direct mount RED X Sync chainrings let you pick the exact gearing you want and quickly swap sizes. X Sync technology keeps the chain where you need it to be, too. X Sync wide tooth, narrow tooth chainring technology provides maximum chain control Laser etched chainring finish is more durable than previous version X Range gearing technology gives you more range and a smoother gear progression, so you re always in the