Golf balls are one of the two most important pieces of a golfer's equipment: golf clubs and golf balls. Golf balls have advanced from chunky, heavy wound balls of fabric and leather to exotic thermoplastics and chemical composites. The more traditional 2-piece and 3-piece golf balls are used by the majority of golfers, while the 4-piece and 5-piece golf balls are used mostly by professionals and advanced amateurs. The standard construction is a dense core surrounded by thinner, lighter mantles, capped with a thin urethane, ionomer or surlyn cover.