Irons are golf clubs with a flat angled face and a shorter shaft than a wood, designed for shots approaching the green or from more difficult lies such as the rough, through or over trees, or the base of hills. As with woods, "irons" get their name because they were originally made from forged iron. High-loft irons are called wedges. The higher the number gets on the scale, the lower amount of angle difference from 90 degrees. Irons are often hybrid, cavity-back or muscle-back. A hybrid is any iron that features a head very similar to a fairway wood; hollow steel or titanium with a shallow, slightly convex face. A hybrid head is usually marginally shallower and does not extend backwards from the face as far as a comparable fairway wood. A Cavity-back iron is any iron in which a small to large amount of the metal across the back of the head is removed, allowing that weight to be re-positioned on the perimeter of the head, farther away from the head's center of gravity. A muscle-back iron is any iron in which there is no cavity on the back of the head, i.e., the weight is more evenly distributed across the back of the clubhead.Wedges are irons with a higher loft than a 9 iron, which is typically lofted at about 42 degrees. Wedges are used for a variety of short-distance, high-altitude, high-accuracy shots such as hitting the ball onto the green ("approach" shots), placing the ball accurately on the fairway for a better shot at the green ("lay-up" shots), or hitting the ball out of hazards or rough onto the green (chipping). There are usually six types of wedges with lofts ranging from 45° to 64°: pitching wedge (PW 48°), gap wedge (GW 52°), sand wedge (SW 56°), lob wedge (LW 60°), and ultra lob wedge (LW 64°)[1]. The pitching wedge is sometimes called or labeled as a 10 iron, and the gap wedge is sometimes called an approach wedge or Utility Wedge and labeled with AW or UW respectively
adapted from wikipedia
