Replace your dry, worn-out OEM rubber half-moon seals with these billet aluminium replacements from Aeroflow Performance. These cylinder head plugs have been specifically designed to replace the problematic OEM plastic seals which become brittle with the constant temperature changes, eventually leaking and requiring replacement again. Machined from billet 6061 aluminium so you never need to worry about replacing them again. They fit into all OEM applications and sealed with RTV liquid gasket which can be cleaned and re-applied after each use.