I'm new to this forum so not sure what the consensus here is regarding resurrecting old threads, but for those doing research who come across this.... I use a HPG Prairie belt with my Exo 3500 pack. Fits and works like it was made for it. I wasn't sure at first because the Prairie belt doesn't have velcro like the Exo belt does, but that hasn't been an issue.I actually tried to sell the Ute because it fits a niche that I don't really have a use for right now. I need daypacks and 8-10 day expedition packs. The Ute is somewhere in the middle of those two, although it compresses down to daypack size very nicely. I'm secretly glad it didn't sell, because I love the prairie belt. It's one of the most comfortable pack belts I have ever used.