absoluteBLACK Oval 104/64 BCD Chainrings greatly improve traction and climbing abilities. They are designed for use with all cranksets with a 104/64 BCD interface, including Shimano, SRAM, RaceFace, FSA, and more. These chainrings allow you to run a 1x system without chain retention issues. The specially designed narrow-wide tooth profile keeps the chain snug, allowing you to leave your chain keeper in the garage. They are crafted from CNC machined 7075 aluminum, and feature an anodized finish for exceptional durability. Ovality has been optimized for each chainring size, ranging from 10.2 - 14.4%, with timing of 110.5-116.3? after TDC (top dead center).