1Adopting hardening technology, it has greater wear resistance, durability, high temperature resistance, corrosion resistance, rust resistance, no deformation, and good impact resistance. 2Provide fast and accurate index conversion function through special tooth profile and slope. Special shaped irregular cut angle tooth profile, better compatible with various of transmission chains, shift gears are sensitive and smooth. 3Hollow design can easily reduce weight to achieve a good balance between strength and weight. The independent small tooth ring is convenient for future replacement and maintenance. 4Easy to install and does not require any adjustments to the transmission system. The unique mountain bike chain design can well control the speed change function. 5Using high strength steel, nickel chromium plated treatment, it is sturdy and durable and has long service life. Item Type: 11 Speed Freewheel Material: High Strength Steel Product Color: As Pictures ShownProduct Weight: Approx. 658g / 23.2oz Speed: 11 speed Gear Ratio: 11-13-15-17-21-24-28-32-36-40-46T 1 x Bicycle Flywheel 2 x GearRing 1 x LockRing