I'm posting more information I found in case someone else is researching. I looked at a couple other brands at the farm show in Kansas City. Collins Enterprises makes 450 and 700 pound models. It's called Backpack. It looked nice but was a bit higher than Stull in price. Applegate is also selling a trailer model as part of it's Feedtrain line. It was more expensive yet and it doesn't have a lot of ground clearance. I was concerned about pulling it through mud and rocks. I purchased the Stull a few weeks ago. It was cheaper and lighter. I wanted lighter because I want to be able to take it off easily to free up the Mule bed. I have been a little disappointed with it. The battery cable was not long enough. I called them and they claim they've never heard a complaint about that. I don't see how it would work on a Mule. Their only suggestion was to add a separate battery just for the feeder. So, I added an extension to the cables and it's working now. I think it will work as expected now.