Caswell Tank Sealer (also known as a gas tank liner) is a 'phenol novolac epoxy'. Why that matters to you is because that means it is a new breed of chemical resistant materials, able to withstand permanent immersion of many harsh solvents, fuels and oils. The higher bond strength reduces the need for a clinically clean surface, as the epoxy actually prefers to bond to a rough rusty surface! Perfect for sealing both fuel and oil tanks, a big plus is that it is also resistant to modern fuels that have high ethanol content. This kit contains enough material to coat approximately a 5 gallon gas tank. Since you mix what you need this allows you to coat multiple smaller gas tanks with just one kit. Caswell tank sealer can be used on steel tanks as well as fiberglass, which means you can now run that cool old fiberglass tank without the ethanol in the gas turning it into a pile of goo! Follow the included instructions for a durable coating that will last for many years, and can even be used to fix tanks that with failed coatings such as Kreem or POR-15. Made in the USA.