The biggest problem I find with the Sullivan and DuBro tanks is that the stopper is so huge that the clunk line starts half way inside the tank. I like the Hayes 2oz. It has a very small stopper with no rubber, the vent is moulded into the tank so there are no brass tubes. The fuel line that comes to attach between the stopper and clunk is black, very flexible and not silicone. A friend of mine uses them for diesel. They are often used on helis as a header tank - at 3 times the regular price.