Note that framesets and bikes come with a spare hanger. If you would like an extra or need a replacement you can order here.
Road Ti frames use the SRAM UDH, which is available at any local bike shop.
Allroad Ti V2/V3 derailleur hangers are for titanium frames with 8 digit serial numbers that begin with W201XXXX or .
Allroad Ti V1 derailleur hangers are for titanium frames with 8 digit serial numbers that begin with 0619XXXX or 0620XXXX.
Allroad AL/ALt derailleur hangers only come in one spec.
You can find the serial number under the bottom bracket.