This is a reproduction Upper Shroud Repair Section, made of Press Molded Fiberglass to be bonded together with your lower shroud halves.
All 1966-1967 Small Block Corvette fan shrouds where made of a composite material, this is a Fiberglass Press Molded assembly that is stronger than the original one, built to take the vibrations from your engine and keep your Corvette running cool
Learn more from the following Mid America Motorworks Knowledge Library article:
Corvette Body Components from Fiberglass to Resin Transfer Molding