Review on Bender Tanks: High-Performance Utility Containers for Racing by Alan Brewer

They work great as they allow you to put the filler hose into the tank and spray fuel all over the car and up the sides. They prevent the filling hose from kinking and you only have to turn the fuel tank slightly to empty it completely. I recommend installing them on a new pitcher fill hose as it's easier to avoid twisting the new hose during installation.