ACDelco Gold (Professional) Marine Spark Plugs are a high quality alternative to Original Equipment (OE) parts. These Marine Spark Plugs are everyday replacement plugs designed for reliability and efficient performance in jet boats, inboards, outboards, and personal watercraft. They can maintain stable operating temperatures under varying loads. Their high-quality copper core and outstanding suppression characteristics deliver reliable performance. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.