Steve, the rivnut tool is an Astro Pneumatic AO1442. Here's an EBAY link to the place I bought mine:
ASTRO PNEUMATIC Metric and SAE 13"Thread Setting Hand Riveter kit AO1442 | eBay
There are a bunch of tools out there pretty much just like this one. I bought this kit because of a review I found on YouTube from The Fab Forums. For all I know, he got his for free from someone who sells them, but he seemed to be happy with it. Probably not the best way to make a decision, but they're all from China and without them on front of you to compare, you don't have many options.
I've set all the inch sizes it will do and it works fine. I did buy a 3/8-16 mandrel since it didn't come with one. After a little depth adjustment on the mandrel, which is easy, it set the 3/8 nuts with little effort. As with anything from China, no way to tell how long it will last.