Narrow 21" long lip is the front extension of the fender. This is a replacement part and may not be enough to repair cutout wheel wells or flared out fenders. If you need more than this 2" piece covers, look for Front Fender Lips. Sold as a Pair.
Louver panel or fender panel extension, replaceable without removing entire fender. Also called lip of wheel well.
Learn more from the following Mid America Motorworks Knowledge Library article:
Corvette Body Components from Fiberglass to Resin Transfer Molding