2D Forcing Stayman

Playing Forcing Stayman (2-Way Stayman), 2C is non-forcing, and 2D is game-forcing. 
 
Responses to 2D:

• 2H with 4 hearts or both 4 hearts and 4 spades. 
• 2S with 4 spades.
• 3C/3D with 5 in the suit.
• 2NT with none of the above.

This convention is frequently used in the precision system, and it is perhaps better than Jacoby Transfers when playing 12-14 NTs.