Feature: 1. High Strength Steel Flywheel: The high strength steel flywheel is crafted with quenching and tempering processes, multi layer plating, and toothdropping design, offering reliable shifting for a better cycling experience. 2. Lightweight Aluminum Crank: The crank is made from lightweight aluminum alloy, providing high strength and compatibility while showcasing a stylish and eye catching appearance. 3. Improved Shifting Performance: The 9 speed bike shift kit features a hollow one piece crank and easy to use derailleur, providing improved shifting performance and a smooth ride every time. 4. Easy to Install and Clean: The bike shift kit is designed for easy installation and maintenance, meaning even beginners can assemble and maintain their bike with ease. 5. Perfect Gifts for All Occasion: Whether you're looking for a present for your husband, wife, boyfriend, girlfriend, or child's bike, this 9 speed groupset makes ideal gifts for holidays, birthdays, or special occasion. Specification: Item Type: Bike 9 Speed Groupset Material: Aluminum alloy Weight: Approx. 2360g/83.2oz Teeth Number: 11 13 16 20 24 30 36 42 50T. Package List: 1 x Flywheel3 x Flywheel Accessory1 x Tail Hook1 x Tail Hook Screw1 x Front Derailleur1 x Rear Derailleur1 x Chain2 x Chain Link1 x Chain Case1 x Left Crank1 x Right Crank1 x Bottom Bracket10 x Crank Accessory1 x Chainring