Optimal Performance : Solo is designed for single chainring conversions with 104mm BCD interface bike crankset. Provides tighter connection between the chain and the ring, and keeps the chain firmly in place. Enhanced Compatibility : It's compatible with 9 to 12 speed chains, making it a versatile and practical option for a variety of different bikes and riding styles. Provides reliable and efficient performance across a range of different speed configurations. Superior Chain Retention : The narrow-wide design locks the chain tightly with its alternating tooth, ensuring maximum security, and less likely to fall off even riding on the toughest terrain. Precision Chain Line : The stepped bolt holes design ensures accurate chain line for crisp shifting and secure chain retention, resulting in seamless transitions and smooth power transfer. Quality Production : Built in tough 7075 aerospace alloy with full CNC finish, Solo has strong resistance to ward off severe vibration and damage from rough trails. The high quality material provides unbreakable durability yet still extremely lightweight. FUNN SOLO NARROW WIDE CHAIN RING is specifically designed for single chainring (1x) conversions with 104mm BCD interface crank sets. CNC narrow wide profile keeps the chain on the ring at all times, in all terrain.