Fluid Film is a rust & corrosion preventive, is used also for underbody coating vehicles. One gallon can undercoat 4 vehicles. Fees for undercoating cars - 500 to 800 dollars, trucks 750 to 1250 dollars. I have fourteen gallons available, 30 dollars a gallon. Fluid Film is also a penetrant & lubricant and has many uses around the farm and shop.