Transfer Flow fuel tank systems are safe, legal, and reliable. Our premier fuel tanks are made from the finest U.S. materials, including 12- and 14-gauge ReliaSteel®, high-yield U.S. aluminized steel that is powder coated for a long lasting, durable finish. Transfer Flow fuel tanks are for every need, including high-capacity replacement tanks, in-bed auxiliary tanks, refueling tanks, and fuel tank tool box combination systems.