Surely, our product can be used for a long time because it has good wear resistance and corrosion resistance, and it also has a compact structure at the same time.No doubt, the screws are made of high-quality materials, which it has good anti-rust performance. And the thickness of the head is only 3mm, which it can protect the crank from being scratched.It is made from aluminum alloy and nylon, is durable to use.There is one size of the product to choose from.Adjuster for alloy bottom bracket of crank.Item Name: Crank PreloaderMaterial: Nylon,Aluminum AlloyFeatures: High Hardness, Corrosive Resistant, Ultra-lightSize Details: Inner Diameter: 30MM/1.18"(Approx.)Thickness: 6.3MM/0.25"(Approx.)Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Crank Preloader1 x Spacer