Marine Flame arrestors are required, by law, for every boat with a gasoline engine. Holley marine flame arrestors are designed to protect your vessel from the potentially disastrous effects of backfire, plus they look great. A properly sized flame arrestor is a must to get the maximum performance from your vessel. A flame arrestor that is undersized will restrict engine breathing as would a dirty air cleaner. Holley offers aluminum, chrome and stainless steel flame arrestors in various sizes. The charts below list these by finish and also their sizes and recommended CFM. The recommended CFM column is a selection guide so that the flame arrestor could be properly sized to the carburetor's CFM capacity and existing space restrictions.