Our premium E*thirteen (E13) Direct mount Oval chainrings are designed for E*thirteen TRS cranks only. It replaces stock round chainring.Size (Mass +/-1g):30T (58g), 32T (62g)Compatibility:E*thirteen TRS, TRS+ and TRS Race Carbon cranks only. 9, 10, 11 and 12spd Eagle compatible.Material:CNC machined 7075 Txxx Aluminum. Long-lasting constructionFinish:Type II anodizingChainline:49mmOvality:Optimized to each size separately. Range: 10.2-14.4% and Timing of 110.5-116.3° after TDC (top dead center) Patent PendingAdvantages of our special Direct mount chainrings:Finest design to provide excellent weight to strength ratioMin 12% lighter over stock round chainringOne of a kind special oval shape (Patent Pending)Greatly improves traction and climbing abilitiesUnique Patent Pending narrow-wide teeth profiles to keep your chain in place for minimum 12 months!Special 3D teeth machining for ultimate mud relief decrease wear and noise dramaticallySuperb quality and great look.You will ride faster