Wheels Mfg. SOLO-XD and SOLO-SPLINE Single Speed cogs are constructed with high-end 7075 aluminum and designed with narrow to wide alternating tooth pattern allowing for superior chain retention. Cogs are optimized for use with Wheels Mfg. SOLO-XD XD/XDR and SOLO-SPLINE Single Speed Conversion kit carrier systems only. Crafted with high-end 7075 aluminum for light weight and extreme durability. Cogs are optimized for use with Wheels Mfg. SOLO-XD XD/XDR and SOLO-SPLINE Single Speed Conversion kit carrier system only. Designed with narrow wide alternating tooth pattern allowing for superior chain retention. Fits 9, 10 and 11-speed chains. Compatible with 12-speed Eagle, KMC, Road and T-Type Transmission flattop chains. Will not work with 13-speed Campagnolo or 12-speed HG+ chains. Item Specifications: Tooth Count: 20, Material: Aluminum, Defined Color: Orange,