Justin Darlington, known as Jus Fly, is a 6'4" dunker from Montreal, Canada with a 50" vertical. He goes up off two feet from a right-left plant, and his signature is the cartwheel between-the-legs.
He is credited with inventing the under-both-legs dunk, which is now a standard entry in the bag of every serious trick dunker and was not a thing anyone did before him. The cartwheel into a between-the-legs into a windmill is the one that went everywhere; he won the opening leg of the Nike+ Basketball Dunk Showcase with it.
2012 was the year that defined his contest reputation. He went through the entire year without losing a dunk contest to anybody, a run that is hard to assemble in a discipline where a single missed attempt can end a round. He has also won at the FIBA Europe 3x3 EuroTour opening event in Bucharest, and the international 3x3 circuit has been a large part of where he competes.
The 50 inch vertical is the engine, but the reason his name attaches to inventions rather than just wins is that he kept adding rotations and body positions to dunks other people considered finished. The cartwheel approach in particular changed what an approach could look like, because it broke the assumption that you run at the rim in a straight line.
He performs with Dunk Elite, the touring group that formed in 2013 and pulled together much of the sport's top talent, and has spent his career competing and putting on shows internationally rather than staying on any one country's circuit.