Wedges are a subclass of irons which have a loft greater than that of a 9-iron (generally more than 44°). Although highly similar in design and construction to other irons, the purpose of wedges is more specialized, and thus they are often regarded as a class unto themselves. They give a very high, short trajectory with a lot of backspin(when hit correctly), all of which cuts down on the rolling distance of a ball after its initial impact. Wedges are thus used for a variety of high-accuracy "utility" shots, such as lofting or chipping the ball onto the green, out of a sand trap, or over or around an obstruction such as trees, rocks or sudden changes in terrain level. A set will generally have two, sometimes three wedges: the traditional pair is a pitching wedge and a sand wedge, to which modern golfers generally add a lob wedge or a gap wedge. Wedges are seldom numbered, being identified instead by their loft (56°, 62°, etc.) or their function:
The pitching wedge (generally labeled "P", sometimes "W") has a loft of 44-50 degrees and is rather similar in design and function to other short irons. In fact, in older sets the pitching wedge often had the designation of "10-iron" and even today most matched sets of irons include a pitching wedge as if it were a numbered iron.
A sand wedge ("S") has a specially designed underside that provides "bounce", allowing the sole to skim over sand and avoid digging in, which combined with a loft of 54-58 degrees makes it suitable for shots from bunkers or from deep rough. Older sets sometimes called this the "11-iron" or "sand iron"; the purpose was the same.
The gap wedge (sometimes "G", but commonly "A", "D", or "U") has a loft somewhere between a pitching wedge and a sand wedge (50-54°). Modern pitching wedges have lower lofts than previous generations, while sand wedges have generally remained the same. The "gap wedge" was introduced to fill this gap between lofts, hence the name. This is the newest type of wedge and as such has little standardization of design, purpose or even name; Wedges in this general range of loft with varying amounts of bounce have been called "Approach", "Dual", "Utility", or "Attack" wedges and designed for a multitude of lies from sand to rough to fairway, depending on player preference.
The Lob wedge ("L") has a very high loft (up to 68 degrees, most commonly 60) and is used for the shortest lob shots (generally 10-45 yds) such as close approach shots, from sand, or difficult recovery shots requiring an extraordinarily high shot and short distance. The highest-loft variations (64° and over) are sometimes called "Ultra Lob", "Flop" or "Final" wedges, used for specialized, extremely high-angle shots such as from the "lip" of a bunker. These are generally made by specialty companies and some argue that their purpose is redundant, as a 60° lob wedge or even a sand wedge can be "opened" for extra loft in situations calling for such a high launch angle.
Given this wide array of choices, the traditional pair of pitching and sand wedges is starting to become less common as players can choose variations of gap wedges to fine-tune the spread of their wedges' lofts. A player may pick an "approach" wedge with low bounce but greater loft than a pitching wedge, say 50°, and a "dual" wedge with a similar bounce but less loft than a sand wedge (like 54°), then pick a 60-64° lob wedge and forgo both of the traditional wedges.