I'm glad to see there are a few other people out in the world that were curious about ball mounts and the different types there were. I was lost when I bought my H3. So I was doing some research on here and didn't find this post but I ended up finding my answer through What Ball Mount Is For Me? - HitchAnything.com. Here it gave me a complete run down on the different types of hitches and even has a calculator function to determine the appropriate drop/rise needed.