Gap wedges only became necessary as changes in club design, namely the creation of cavity-backed irons, required club manufacturers to de-loft the numbered irons and pitching wedge. This is because with the new club designs the trajectory of shots changed to higher launch angles despite the loft angle remaining the same as before. To compensate, loft angles of the club faces were reduced. However, this did not happen to the sand wedge because of its very specific purpose of digging balls out of sand bunkers. Thus, a gap in distance and loft angle between the sand wedge and pitching wedge was created which previously did not exist. The gap wedge was created in the 1990s to provide an option between these two clubs.
The gap wedge has a loft ranging from 50 to 54 degrees and is used when neither a pitching wedge, with a loft of 45 to 49 degrees, nor a sand wedge, with a loft of 54 to 56 degrees, will accurately get you to the green.
The gap wedge--aptly named, as it fills the gap between the pitching wedge and sand wedge--is the ideal approach wedge when hitting from 60 to 80 yards to the green.
The angle of the gap wedge is best for hitting shots with a higher and shorter trajectory than a pitching wedge, yet with a lower and longer trajectory than a sand wedge.
The gap wedge is also known as the "utility" wedge, "approach" wedge or "all" wedge.
The gap wedge, with its high loft and more spin, enables the ball to roll quickly to a stop on the green, allowing for more accurate shot making.
Anywhere from 120 yards in toward the green is known as the "scoring zone." Allowing more wedges in your bag to accurately get you to the green and close to the pin will work in your favor.