Rear Wheel Well Repair Panel, RH.
This is a repair panel to return to stock wheel wells if a previous owner has radiused the wheel wells for bigger tires. This panel has the lip of the wheel well and the correct arch. This will save you from major panel replacement.
Learn more from the following Mid America Motorworks Knowledge Library article:
Corvette Body Components from Fiberglass to Resin Transfer Molding
ACI