Full twist jump
Swing out and back to the platform, where you turn one hand as if you were going to turn around and come back to the platform. At the front end, push out into your half turn, and as your body comes round into the set to swing back the other way, let go of the bar and continue the turn to make the catch. The trick is basically a half turn swing and a half turn to catch rolled into one.
You can find out more about this trick in following books: