2PCS Aluminum Bike Rear Derailleur Hook Extender Mountain Bike Accessories Features: 1.This product is used for rear derailleur extension, most of the tail hooks are compatible. 2.The extension is equipped with a screw that needs to be installed with a 6mm wrench to expand the flywheel for smoother shifting. 3.6 colors to choose from, make your mountain bike more personalized. 4. Aluminum alloy material, CNC process, strong and solid, very durable. 5. The product is used to lengthen the tail hook, mainly used to modify the flywheel to increase the style of use, excellent accessories for bicycle enthusiasts. Specification: Name: Bicycle tail hook extender Material: aluminum alloy Weight: about 13g / piece Color: black / red / blue / gold / purple / green Package includes: 1 * extender Note: 1. Due to manual measurement, please allow 1-3mm error. Please make sure you don't mind before ordering. 2. Please allow 1-3g weight error. Please make sure you don't mind before ordering. 3. Due to different lighting of photos and differences in monitors, the pictures may not reflect the actual color of the object. Please make sure you don't mind before ordering, thanks! Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.