Rubber-backed firewall insulation mounts to interior compartment side of firewall or cowl (behind interior dash components). Pieces are precision cut and molded to fit specific Corvette applications. Correct fitment for 1973-1975 Corvette. All firewall insulations are designed for heater equipped Corvettes and include scribed cut-outs for air conditioned option. Must order firewall insulation retainers separately - Zip Corvette # M-2609C.