To use these double - ended cone wrenches, first, identify the size of the nut or cone flat you need to adjust. Then, pick the appropriate end of the wrench. Make sure it fits snugly before applying pressure. When using, turn the wrench gently but firmly to avoid stripping the nut. For safety, always wear gloves. To maintain these wrenches, after each use, wipe them clean with a dry cloth. If they get dirty, you can use a mild soap and water solution, then dry them thoroughly. Store them in a dry place to prevent rusting. If you're unsure which size to use for your specific project, give us a call, and we'll help you out.