SRAM RED E1 X-Sync Direct Mount Chainring SRAM's light, stiff, and durable direct mount RED X-Sync chainrings let you pick the exact gearing you want and quickly swap sizes. Features 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 right gear Improved aerodynamics for time trial and triathlon SPECIFICATIONSMaterial Aluminum Round or Oval Round Direct Mount Type Direct Mount SRAM 8-Bolt Tooth Count40Drivetrain Speeds12Offset6. 5 | Sram | Red E1 X-Sync Direct Mount Chainring 40T | Aluminum