1、Smoother Shifting: Flywheel adopts high strength steel plate, quenching process, tempering hardening treatment, multi layer electroplating, anti rust, tooth dropping design, smoother shifting. 2、Light Weight Chain: 8 speed bike shifting groupset, low friction chain, stable shifting, light weight and long service life. Perfect for upgrading your mountain bike, road bike, etc. 3、Strong Compatibility: The crank is made of aluminum alloy, which is light in weight, stylish in appearance, dazzling in shape, strong in the axis and strong in compatibility. 4、Gifting Choice: It is a gift for your husband, wife, boyfriend, girlfriend, or for your children, or as a back to school gift, Christmas gift, Valentine's Day gift, Mother's or Father's Day gift, Thanksgiving gift or new Year's gift. 5、Stable: Professional 42T flywheel bike groupset, providing a stable drivetrain. With chain connector to reduce chain drop, flapping and noise. Item Type: Bike Flywheel Gear Kit Material: Aluminum Alloy Gross Weight: 2200g / 77.6oz Flywheel Gear Ratio: 11 13 16 20 24 30 36 42T 2 x Crank 2 x Crank Accessories 4 x Crank Srewbolt 4 x Crank Screw 1 x Central Axis 1 x Dial 1 x Rear Dial 1 x Rear Dial Screw 1 x Tail Hook 1 x Flywheel 3 x Flywheel Gear 1 x Crankset 1 x Chain 2 x Chain Connector