Originally Posted by Winfried

I ordered the "LitePro Braze-On K-Series Front Derailleur Clamp Adapter For Dahon K Frame".

Litepro Braze on K Series Front Derailleur Clamp Adapter for Dahon K Frame | eBay

Incidently, what Dahon bikes use the K frame, so I can check what they look like, especially their geometry (seat tube ↔ bottom bracket)?