High Quality: This wrench is made of high quality carbon steel, works sturdy and stable, suitable for daily maintenance. For assembling and disassembling the bottom bracket. 2 IN 1 DESIGN: This wrench has 2 sides. One side is for the bottom bracket and the other is for the crank. It is designed for crank and bottom bracket removal and installation. (When removing and installing the crank cover, first loosen the two crank bolts next to it, then use the crank cover tool to remove the crank cover. It will be very easy.) Easy to use: key + crank tool. Length: Approx. 22 cm/8.66 inches, comfortable in hand. This product can be used with Shimano Hollowtech 2 and above. Fits: This bike wrench comes with a preload clamp tool. A very useful tool for your bike repairs. A wrench is the ideal accessory for any home bike mechanic or cyclist. Note: When installing the bottom bracket, you must distinguish between left and right, align the teeth and screw in by hand first, if you can't turn it by hand, use a tool. If the bottom bracket is not firmly seated, the tool cannot be fixed with bolts, it is recommended that you stop and check whether it is installed correct. Do not brute force the bottom bracket or frame.