I was adjusting the deraileur on my mom's 2003 Giant OCR 2 and somehow broke off that tab that attaches the front derailleur to the seat tube. It's a piece of aluminum which is bolted onto the frame and also bolted onto the derailleur. It has a slot in it for the derailleur to move up and down. I have no idea what this is called or where to find a new one. Are they particular to the bicycle or is it a generic part? Tomorrow I will try phoning some bike shops.