and firm core. They induce a greater amount of spin from lofted shots (wedges especially), as well as a sensation of softness in the hands in short-range shots. However, these balls require a much greater swing speed and thus greater physical strength to properly compress at impact. If the compression of a golf ball does not match a golfer's swing speed, either a lack of compression or over-compression will occur, resulting in loss of distance. Other choices consumers must make include brand and color, with colored balls and better brands generally being more expensive. Practice/range balls A practice ball or range ball is similar to a recreational golf ball, but is designed to be inexpensive, durable and have a shorter flight distance, while still retaining the principal behaviors of a "real" golf ball and so providing useful feedback to players. All of these are desirable qualities for use in an environment like a driving range, which may be limited in maximum distance, and must have many thousands of balls on-hand at any time that are each hit and mis-hit hundreds of times during their useful life. To accomplish these ends, practice balls are typically harder-cored than even recreational balls, have a firmer, more durable cover to withstand the normal abrasion caused by a club's hitting surface, and are made as cheaply as possible while maintaining a durable, quality product. Practice balls are typically labelled with "PRACTICE" in bold lettering, and often also have one or more bars or lines printed on them, which allow players (and high-speed imaging aids) to see the ball's spin more easily as it leaves the tee or hitting turf. Practice balls conform to all applicable requirements of the Rules of Golf, and as such are legal for use on the course, but as the hitting characteristics are not ideal, players usually opt for a better-quality ball for actual play. Recycled balls Players, especially novice and casual players, lose a large number of balls during the play of a round. Balls hit into water hazards, penalty areas, buried deeply in sand, and otherwise lost or abandoned during play are a constant source of litter that groundskeepers must contend with, and can confuse players during a round who may hit an abandoned ball (incurring a penalty by strict rules). An estimated 1.2 billion balls are manufactured every year and an estimated 300 million are lost in the