Feature: 1. High Strength and Wide Compatibility: Plastic steel body, steel guide plate, high strength, durability and impact resistance, wide compatibility, smooth speed change, hollow design for light weight. 2. Smooth Shifting and Reduce Chain Wear: PA nylon wear resistant guide wheel, silent, smooth and non wearing chain. Middle leg guide plate design, 11 teeth nylon silent guide wheel, lightweight design to reduce chain wear and smooth shifting. Built in high tension spring, oblique pendulum zoom to avoid collision. 3. H/L Adjustment Screw: Debug these two screws to ensure that the chain is between the largest and smallest pieces of the flywheel. H is the high position and L is the low position. 4. Tension Screw: The rear gear shift and rear tail hook are used to adjust the rear derailleur tension, which can control the tension and affect the gear shift response time. 5. Threading Protection: Speed changing threading protection, brake thread bayonet design on the driving arm, double layer threading protection, precise fixing of the thread core, and smoother speed change. 6. Applicable Models: The 9 speed dedicated rear derailleur transmission has good compatibility and is suitable for multiple brands of variable speed models. It is compatible with the maximum number of teeth of the flywheel 32T, and the total gear capacity is 39T. Specification: Item Type: Bike Rear Derailleur Material: Plastic Steel Main Material + Steel Guide Wheel Arm + PA Nylon Guide Wheel Product Color: As Pictures Shown Product Weight: Approx. 254g / 9.0oz Speed: 9 Speed Installation Method: Direct mount bike rear derailleur (the frame needs to have a rear derailleur tail hook). Package List: 1 x Rear Derailleur Note: The speed of the rear derailleur must correspond to the flywheel/chain. For example, a 9 speed rear derailleur must be matched with a 9 speed flywheel and a 9 speed chain. They must not be confused with each other to avoid damage to the accessories.