Exaxt Fit belts are produced for California Cycleworks, which is the business run by the guy who made this video, Chris Kelley. They are specced to be at least as good as oem belts but are sold at a much lower price. Here is a demonstration of how strong they are compared to oem and another competitor, presumably Dayco. Here is a demo of how precisely they are designed and manufactured: and another of how they are checked for precise length:
