"Prodigy" was a name to denote their budget line of gaming peripherals. But with how popular the G403 turned out, they decided to drop the moniker from it altogether. They have slapped the Prodigy name onto the G203 though because that actually is more of a budget mouse in Logitech's line-up. So to answer your question, they're the same mouse. Although if you get a G403 with Prodigy labeling on the box, it's probably a much older unit.