S21 Lock Nut for KTM derailleur hangers: D476, D477. You will need Pilo S41 special trail tool to tighten S21 properly.
Made by Pilo.
For any questions please e-mail us:
To be sure if this the right part, please send us photos of:
1. Your derailleur hanger from both sides;
2. And if possible bike‘s frame part photos, where dropout was attached.