Feature:1. The shift will be smoother and quieter.2. Perfect replacement of old flywheel, perfect operation, for best performance and maximum safety and life.3. Suitable for mountain bike, bicycle, etc.4. High pressure steel plate, nickel and chromium plating treatment.5. Hollow design, weight reduction, super wear resistant steel.Specification:Condition: 100% Brand NewItem Type: FreewheelMaterial: chromium-molybdenum steelColor: as picture shownSpeed: 9/10/11/12 SpeedOption: 9S 11-32T, 10S 11-36T, 11S 11-42T, 12S 11-50T9S 11-32T weight: 326g10S 11-36T weight: 418g11S 11-42T weight: 542g12S 11-50T weight: 607g.Package List:1 x Freewheel3 x AccessoriesNote:Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.