Ten-pin bowling over the Model A), all three versions are still in widespread use. The television age of the 1950s also helped to increase the popularity of ten-pin bowling, as images of the sport began to enter the homes of millions across the United States. Nationally televised programs like "Jackpot Bowling" and "Make That Spare" became popular on Friday nights from the late 1950s into the early 1960s. Following many years of debate over what constituted a professional bowler versus an amateur, Eddie Elias founded the Professional Bowlers Association (PBA) in 1958. The PBA's "Pro Bowlers Tour" became a permanent part of
Bowling ball diameter in the range of to . The surface of the ball is required to include markings to indicate the manufacturer's brand name, the name of the ball, the center of gravity (before drilling), the orientation of the core (the Pin), and the axes of the high and/or low radius of gyration (as applicable). Additionally, markings must include an individual serial number and the logo of the USBC. Holes are allowed to be drilled into a bowling ball for a variety of reasons, and bowlers must be able to demonstrate that such holes can be used as claimed. Up to