Specifications Hign-concerned Chemical:None Type:MTB Bike Freewheel is_customized:Yes Model Number:1050SLR Sensitivity:108 Sounds Flywheel Adjustable Gear Number:10-SPEED Material:STEEL Gear Teeth:11-50T Freewheel Speed:10 Origin:Mainland China Components:Freewheel Ultralight MTB Bike 10 Speed 11-50T SLR Cassette Color: Black-silver Material: sprocket:steel spider :aluminum alloy Ratios: 11-13-16-20-24-28-32-38-44-50T Weight : About 365g For HG System UNIQUE CASSETTE STRUCTURE Our cassette uses a unique hybrid structure. Use 7075 aluminum to machine our largest four cogs. Then the next three steel cogs are riveted on an aluminum spider, other three cogs are replaceable, you can easily find a replacement cog from any bike store. WIDE GEAR RATIO Instead of traditional 11-13-15-18-21-24-28-32-36-42-50 gear ratio, now we changed to11-13-16-20-24-28-32-38-44-50T. With a smoother gear ratio, it will be easier for rear derailleurs to shift. IMPROVED SHIFTING PERFORMANCE About the shifting performance, we designed our tooth profile dedicatedly, the earlier version had chain-drop problem when back-pedaling. That also caused the aluminum cogs to break sometimes. But now we use a narrow-wide tooth design to avoid the chain drop when back-pedaling. You can tell that from our test video. MASS COMPATIBILITY Our cassette has extremely wide compatibility, the cassette is compatible with traditional 8-10 speed MTB splined freehub. That means you can install the cassette without any modification to your earlier wheelsets. The cassette is also compatible with most MTB groupset and doesn't needs any modification.