Wedges
Hitting the ball with wedges is about producing
right trajectory and backspin of your golf shots.
These clubs in your bag are usually swung at less than your full
normal swing. It is mostly used for less than 100 meters
accurate shots to the hole.

Loft-Angle
Loft angle is the most important factor to consider for your
impact launch angle to produce the desired trajectory and backspin.
A golfer will find it easier to play with
certain loft-angle than to play with different swing rhythm and
tempo to launch the ball.
Length
The length of the wedge is always the shorter clubs in your bag.
These shorter clubs will have the least swing resistance to any
tempo you adopt and they are meant for directional and accurate
shots rather than for distance. Therefore golfer should select
the right length to suit their most comfortable posture to produce
pin-line shot.
Bounce-Angle & Sole Width
Why Sand Wedge is for sand bunker play?
The Bounce-Angle and sole width of a sand wedge is to prevent
the head from dipping excessively into the sand under the ball.
This is important because the texture of the sand could vary.
Why the swingweight is always heavier?
The Sand wedge is usually played with a much shorter swing. Therefore
the swingweight of a Sand wedge is usually higher than any other
clubs because the feel of more mass on the head help it move
through the ball when the head speed is slow.
Philip Ang, 1999-2000 Winner International Clubmaker of the
Year
conferred by Golf Clubmakers Association (GCA) - USA compiles this article from Golfsmith Tech
Report.