Ten-pin bowling regulations, identification letters and numbers, and general wear from normal use. For much of the history of bowling, bowling balls were made using a three-piece construction method. Starting in the mid-1990s, however, most manufacturers switched to a two-piece method. In response to these innovative ball designs, the American Bowling Congress placed further restrictions on the technical characteristics of the ball such as the radius of gyration and hooking potential. A game of bowling consists of ten frames. In each frame, the bowler will have two chances to knock down as many pins as possible with their bowling ball. In games
Ten-pin bowling Track, DV8, Roto-Grip, Hammer, Circle Athletic, Columbia 300, Dyno-Thane, Fun Balls, Legends, MoRich, Robby, and Via Bowling. Specially designed shoe design and manufacture is also a significant enterprise that many companies have gotten involved in next to ball production. Some of the major shoe designers are Circle, Dexter, Etonic, and Linds. Individual stores that sell the merchandise made by these companies specifically for ten-pin bowlers are called pro shops. In the United States, bowling equipment sales totaled US$215 million in 1997 which is around the same figure as in 1996 when the Sporting Goods Manufacturers Association (SGMA) released their reports.