The Titan® is an excellent option for convenience stores. They are available in standard sizes ranging from 5,000 to 29,600 gallons, and the tanks can be single or multiple compartments. Highland Tank’s patented Titan® technology extrudes 100 mils of high-molecular weight polymer secondary tank to a heavy-duty UL-58 steel primary tank to assure 100% secondary containment. The process utilizes high heat and pressure to create a virtually damage-proof outer thermoplastic tank. Read more.