Golf clubs have traditionally been arranged into three basic types. Woods are large-headed, long-shafted clubs meant to propel the ball a long distance from relatively "open" lies, such as the tee box and fairway. Of particular importance is the driver or "1-wood", which is the lowest lofted wood club, and in modern times has become highly specialized for making extremely long-distance tee shots, up to 300 yards (270 m) or more in the hands of a professional golfer. Traditionally these clubs had heads made of a hardwood, hence the name, but virtually all modern woods are now made of metal such as titanium, or of composite materials. Irons are shorter-shafted clubs with a metal head primarily consisting of a flat, angled striking face. Traditionally the clubhead was forged from iron; modern iron clubheads are investment-cast from a steel alloy. Irons of varying loft are used for a variety of shots from virtually anywhere on the course, but most often for shorter-distance shots approaching the green, or to get the ball out of tricky lies such as sand traps. The third class is the putter, which evolved from the irons to create a low-lofted, balanced club designed to roll the ball along the green and into the hole. Putters are virtually always used on the green or in the surrounding rough/fringe. A fourth class, called hybrids, evolved as a cross between woods and irons, and are typically seen replacing the low-lofted irons with a club that provides similar distance, but a higher launch angle and a more forgiving nature.
A maximum of 14 clubs is allowed in a player's bag at one time during a stipulated round. The choice of clubs is at the golfer's discretion, although every club must be constructed in accordance with parameters outlined in the rules. (Clubs that meet these parameters are usually called "conforming".) Violation of these rules can result in disqualification.
The exact shot hit at any given time on a golf course, and which club is used to accomplish the shot, are always completely at the discretion of the golfer; in other words, there is no restriction whatsoever on which club a golfer may or may not use at any time for any shot.
In stroke play, it is used to calculate a net score from the number of strokes actually played during a competition, thus allowing players of different proficiency to play against each other on somewhat equal terms. In match play, the handicap difference between players is used to determine the number of strokes the high handicap player should receive from the low handicapper during the playing of their round. The higher the handicap of a player, the poorer the player is relative to those with lower handicaps.