Brand unknown, was dismounted from 1995 Bianchi frameset (but I'm not really sure that it was original). The extension is about 100 mm (center to center). A lot of wear and tear. I'm almost sure it is 26.4 because it cannot hold 26.0 handlebar without thin shims.
Looking for USD 15 posted to Europe, offers accepted.
UPD: sold locally.
Looking for USD 15 posted to Europe, offers accepted.
UPD: sold locally.
