●MODEL: RD-TZ31A Black Rear Derailleur,Suitable for 6/7speed. ●PERFORMANCE:Forged with high hardness aluminum alloy.The hollow weight-reduction design is adopted,and the speed change is more stable. ●PRECISE ADJUSTMENT: High-hardness aluminum alloy body adjustment, adjustment is more precise. It can be adjusted slightly in multiple places to ensure accurate speed change performance. ●INSTALLATION:Fast and convenient installation and easy maintenance.(Note:The bike rear derailleur is direct mount,not hub bolt mount .Please check the mount type of the original part before ordering.) ●SCOPE OF APPLICATION:Suitable for mountain bikes, station wagons, folding bikes, etc.If you have any questions,please feel free to contact us.We will provide timely response and quality service.