Fit Link - Braze On Front Derailleur Adapter - Junior's Solution
New 31.8/34.9mm Bicycle Front Derailleur Braze On Clamp Band Adapter Aluminum Alloy Straight Hanging Front Derailleur Ring Part|Bicycle Derailleur| - AliExpress
Origin8 Direct Mount Adapter Braze-on Adapter Clamp 34.9mm Black – The Bike Hub