Durable material: the bicycle bottom bracket washers are made up of anodized aluminum, which fit for 7 8 9 10 11 speed card freehub conversion and button bracket BB adjustment; And the material is lightweight and durable, supporting long term use; They can help you get good symmetry with minimal effort, and you can use these bicycle handle washers safely Multi functions: the bike speed cassette washer can be applied for solving several problems; Firstly, you need to use the bike speed cassette washer to adjust when the the tooth plate of your bike touches the frame or the crank touches the frame; Secondly, the central shaft needs to be equipped with a speed cassette washer when the front shift gear can not come down Change the speed: these aluminum alloy flywheel hub washers can install 10 speed flywheel boxes to 11 flywheels, 7, 8 and 9 speed flywheel boxes to 10 11 speed flywheels, and 7 speed flywheel boxes to 8 and 9 speed flywheels Just in case: the bicycle bottom bracket washer is lightweight and easy to carry due to the small size; You can put the bicycle bottom bracket washer in your backpack just in case; After adding the washer, you will find that it can be locked by your flywheel cover to achieve shifting You will get: the package includes 20 pieces quick acting box type bicycle washers, including 4 pieces of 1 mm, 4 pieces of 1.5 mm, 4 pieces of 2 mm, 4 pieces of 2.5 mm, 4 pieces of 3 mm, the color is for you to choose