Sea Foam is Alcohol, Mineral Oil, and Naptha....It's all on the MSDS data sheet. The Alcohol consolidates the water in the system, the Mineral Oil lubricates upper cylinders and in the case of 2 cycle engines, the whole workings of the engine, the Naptha dissolves gum, varnish, and carbon. WW says the lowest price always, but sorry folks, that is not always true. In the case of SF I can get it from a farm store by the name of Attwoods for over a buck cheaper. But I shop WW often and they have the best oil prices in town; this town anyway.