Replacement Top Flange for Guerrilla Air Myth Regulators. This piece replaces the very top of the regulator and is unique to the Guerrilla Air Myth system. Ever drop your tank and damage the lip around the top of the threads? You can now replace just the "lip" or top flange without needing to purchase a new bonnet or new regulator. Compatible only with Guerrilla Air Myth Regulators.