DURABLE MATERIAL:This cassette is constructed of high strength steel, anti-rust, non-deformation, wear-resistant, high performance of durability. SPEED PROMOTION:The 8/9/10/11/12 speed cassette provide fast riding speed with less effort needed. Reliable to use, applicable to mountain bike freewheel.Applicable for Bike Chain Ring Range: 11-40/42/46/50/52T.Cassette Cogs: As pictured. NO NOICE:The 8/9/10/11/12 speed cassette can promise smooth rotation of chain without much noise.Hollow design,lighter weight. PRECISE:High precision thread ensures close connection with the bike hub and smooth operation.The sprocket guides the chain correctly for a smoother ride. Application:This Freewheel is one of the strongest and most durable flywheels on multi-speed bicycles. Suitable for mountain bikes and folding bikes, hybrid bikes, city bikes, fat bikes, beach cruising bikes and so on. Easy to Install:/9/10/11/12 Speed Freewheel Easy to install, no need to adjust the shifting and directly replace the old damaged flywheel, it is a great accessory for mountain bikes and variable speed bikes. Specification: Compatible with SRAM / SHIMANO / SENSAH shifting system HG freehub Condition: 100% Brand New Item Type: Freewheel Material: chromium-molybdenum steel Color: as picture shown Speed: 8/9/10/11/12 Speed Diameter: 22.2 mm (standard) Option: 8 Speed:11-40T,11-42T,11-46T 9 Speed:11-40T,11-42T,11-46T,11-50T 10 Speed:11-40T,11-42T,11-46T,11-50T 11 Speed:11-40T,11-42T,11-46T,11-50T,11-52T 12 Speed:11-40T,11-42T,11-46T,11-50T,11-52T Package List: 1 x Freewheel