Very much enjoyed our time with Wild West Rafting! Our guide was Jake, he was a bundle of energy and kept our groups enjoyment level up!
You are issued a life jacket, and if you need it water shoes. You will not be issued a helmet (and you won't need one), a few rapids, but nothing dangerous. You can fall out, if you want to, but there is no major threats.
Good views in the Yellowstone, and a quick two hour trip was a good little adventure!