There is not such thing. Sure the media likes it, they like anything they can use as bait. Comparing boxers in different weight classes is like comparing boxers from different generations. Its fun to talk about, but its all speculation. Roy Jones was considered P4P for a long time. But look what happened when he got hit solid. Same is gonna happen to mayweather if he messes with Shane Mosley. Mosley is just as fast and WAY stronger. Bad move Mayweather.