Features:1. Made of quality aluminum alloy with CNC machining, sturdy and firm, durable and corrosion-resistant.2. It is used to lengthen the rear dial chain, and apply to mountain flywheel 0T/ 42T/ 46T/ 50T highway flywheel.3. Make the flywheel speed change more smoothly.4. Easy to install and remove. 5. Great accessory for cycling enthusiasts.Specifications:Material: Aluminum AlloyOptional Color: Red, Black, BlueTotal Length: Approx. 62 mm/ 2.44 inchHeight: Approx. 23.5 mm/ 0.93 inchThickness: Approx. 11.6 mm/ 0.46 inchHole Distance: Approx. 40 mm/ 1.57 inchWeight: Approx. 31 g (Included screw)Packing List:1 * Bike Rear Derailleur Hanger1 * Screw.Note: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.