They are fuel efficient offering great savings in comparison to other tanks.
Two tanks combined work to prevent the danger of leaks so they save money.
Leaking oil can cause issues and require expensive clean-up costs, so these tanks are popular due to the design and safety.
They are highly efficient in storing fuel. The beauty of these tanks is the additional tank that is incorporated in its construction, which will contain any fuel that gets through the first tank to prevent leaks. This also protects the inner tank from vandalism due to the clever design.