I used to use Flitz on a Nickel Colt SAA I had, along with some knife bolsters. If my memory serves me well, I believe its uses were restricted to nickel and silver. This product came in a tube like toothpaste and was more "liquidy" than what you'd usually associate with wax. Based on these things I would think that the Flitz product at the site you give is a new formula(?)
For the past 10 years or so, I've stood by Renaissance Wax. A little pricey, but well worth it in my humble opinion. A good thing to remember when weighing the cost is that a very little goes a very long way.
Best Regards - Marc