I'm needing a few Pax for an upcoming trip. What's the difference and why would I order one over the other. Price is about the same. Appearance is about the same. Sizes vary slightly. Maybe a difference in construction and mounting, but the mounting points and mounting hardware 'look' conceptually the same even if the sizes are slightly different. How are the spouts? It looks like they come with those stupid USA spouts that are supposed to keep me from pouring fuel on a bonfire but when I do that I always just take the cap off for a bigger bang. Which is the best replacement. I hate to drop extra money on a new spout that works when I buy a new spout that doesn't... Is it called an "Eco spout" because it requires additional plastic to make? Is it green to make me feel better about saving the planet? I'm so awesome.