2 Flannery

This is a special opening for hands, with exactly 4s and 5s, which are too weak to bid reverse.
All hands with 10-15 HCP and 4540 4531 4522 4513 and 4504 are opened 2.
The opening has great values in preempt as well in finding the right contract yourself.
Marty Bergen writes: "It is fun to play and effective, comes up reasonably often and is not difficult to remember"
Like after any other well described and limited opening, after flannery responder is the Captain and opener bids only when he is asked to describe his hand.
pass Long diamonds misfit hand
2 or 2 to play
3 / 3 6+ cards in the suit bid. Invitational to 3NT. The bid asks, if opener has Hx in the suit bid.
3 or 3 invite to game
3NT to play
4 / 4 Transfer to 4 / 4 (To allow opener to play the hand)
4 or 4 to play
2NT Strong, unlimited, game force, asks opener to describe his hand.
Opener describes his hand as follows

2 2NT
?

 
3 4513 distribution any strength (10-15 HCP)
3 4531 distribution any strength (10-15 HCP)
3 4522 distribution minimum
3 4522 distribution maximum
3NT 4522 with 1 honor in each minor
4 4504 distribution any strength (10-15 HCP)
4 4540 distribution any strength (10-15 HCP)
This structure is adopted from "Better bidding with Bergen" page 92 ff.
You find there a lot of instructive examples too.