The less you have the more he has. Double then cue-bid shows the best hand imaginable. In suit, show good hand, good suit. To play - gambling style. In auctions where a suit is agreed upon, a jump to 4NT asks for Aces.
Partner chooses the best fit.
It is alertable as are all the Flannery bids, and askes for opener's shape. He rebids in the fragment at the three level showing a singleton in the fourth suit. He rebids a biddable Minor at the four level to show a void in the fourth suit. Three No Trump rebid shows a maximum with at least Qx in each Minor. Two Spade and two Heart responses are to play.