Description: Brand: SNAIL Type: Single speed Color: Black,Red,Blue,Green,Gold,Purple Material: Aluminum alloy 7075-T6 Bolt Center Diameter: 104mm BCD Teeth: 34T (Round/Oval,optional) Thickness: 4mm (1.9mm Narrow, 3.7mm Wide) Compatible with: 7/8/9/10/11/speed chains (for Shimano/SRAM/FSA crank) Narrow Wide tooth profiling ensures ultimate chain retention with 1x chains. Narrow-wide tooth profiling prevents chain drop without a chainguide √Process: Full CNC CNC engraving and milling, anodic oxidation, full of the laser marking √Function: Minimize the probability of chain, simplifying the variable speed system, minus the excess weight.