Phil . . . . I learned about MMO from a fellow boater more than 25 years ago. Since then, I have used it continually at the recommended rate of four ounces per 10 gallons of fuel for the twin Perkins diesels in our Gulfstar trawler, the single Cummins diesel in our American Tug 34 plus our gas powered Honda Accord,Toyota 4-Runner and Nissan Pathfinder vehicles. MMO has been around since the late 1920s. Among its faithful followers are aircraft and truck mechanics, shrimp boat captains, industrial equipment operators, pleasure boat owners and our own Bob Smith. One WWII Corps of Engineers veteran said, "If it hadn't been for that stuff, we never would have won the war in the South Pacific." Also, a mechanic said that when he gets into an engine, he can nearly always tell the owner has been using MMO because of how clean the internal components are. As for the Gulfstar, MMO increased fuel efficiency by between 8 and 10 percent and I estimated it cut in half the amount of exhaust smoke resulting from powering up after extended idling in navigation locks. Without doing the calculations, I estimate I'm getting similar results on the AT-34 and the vehicles. MMP did, however, cure a problem I was having with a Stihl blower that was sporadically dropping below maximum RPM. So I now use it in all my small equipment. I have never used any other additive, nor do I intend to. Neither do I have any financial interest in the company. I talk up products with which I have been more than satisfied and MMO is one of them. Fred Myers Formerly aboard Liberty Belle