Nice simple auction :)
1♦ = Precision, could be doubleton.
1♥ = natural
1NT = 11-13 balanced
2♦ = artificial, GF
2♠ = 4♠, 2♥
2NT = asking
3♠ = exactly 4=2=3=4 shape
4♠ = keycard in diamonds
4NT = 1 keycard
5♣ = Queen ask
5♠ = Q♦ + K♠
Summary: Declarer is known to be 4-2-3-4, dummy is very likely to be 5-4 in the red suits (2NT was probably looking for a diamond fit), although 4-4 is possible.
Benefits include:
Plus... it's free!