These retainers are necessary for the installation of a new urethane front bumper. The Center Lower Front Bumper Retainer is the most important because it bears the majority of the weight of the bumper. We strongly recommend that you DO NOT reuse your old retainers as they might be rusted, bent or damaged. These GM style retainer pieces will ensure the proper fit and look of your new 1973-1974 Corvette Urethane Front Bumper!