Ports provided on both inner and outer tanks for easy access Heavy-duty forged steel port flanges allow for use with all necessary vents, fill ports and pumping equipment Protective powder-coat finish looks great and extends durability The Midwest Industrial Tanks Double-Wall Fuel Storage Tank has a unique double-wall clamshell design that meets SPCC regulations, eliminating the need for a secondary containment tank. Constructed with a 12-ga. carbon steel outer tank that fully contains the entire contents of the 10-ga. carbon steel inner tank. 250-gal. storage capacity. UL listed.