- High hardness material Made of durable aluminum alloy and steel, this design protects the frame threads of your bike while maintaining strength. - Seamless performance with double bearings Double bearings provide smooth operation and enable precise speed adjustments while cycling. - Fits a range of frame sizes Compatible with 142 to 148 mm transmission frame, with a convenient caliper barrier for improved functionality. - Easy maintenance access Facilitates lubrication and inspection of the rear mechanism, making it easier to keep your bike in top condition. 2-3 practical use scenarios - Scenario 1: Upgrading a bike with a 142-148 mm transmission frame to improve rear mechanism durability and stability, while protecting frame threads. - Scenario 2: Regular maintenance between rides, using easy access for lubrication and inspection to keep the rear mechanism performing well. - Scenario 3: Riders who require smooth, reliable speed adjustments on varied terrain, benefiting from double bearing operation and consistent performance.