FIFTY-FIFTY 104BCD Narrow Wide Chainring, Single Chainring for 9/10/11-Speed with 4 Alloy Chainring Bolts The new narrow-wide teeth design increases chain retention, wear life, and reduces friction and noise. With 2mm sims included with 32T,34T,36T to compatible with 2x and 3x crankset. Larger wide tooth design provides maximum ring durability and drop performance. Shimano tool-less fixing bolt design, only a 5mm allen key to install the chainring. One Year Warranty and 100% Money Back Guarantee.