Material: special tool steel, hardened and tempered surface finish: chrome plated in accordance with EN12540 The hexagonal section of the wrench is SW10. This allows for loosening and tightening nuts of this size and for hanging the wrench. How to use the device: The wrench is designed for tightening and loosening front sprocket nuts. Start tightening with the outer end, and once the nut is properly tightened, use the narrower end of the wrench, which is angled to allow for better force transfer during the final tightening phase. When loosening the nut, use the wrench sides in reverse order.