Tennisbollar

Tennis balls, or tennisbollar, are small hollow spheres used in tennis to be struck by rackets. They are typically made of a pressurized rubber core encased in a felt cover. The standard ball is bright optic yellow for visibility on different court surfaces, though white balls are used in some events or older courts.

The official specifications set by the ITF require a diameter of 6.54–6.86 cm (2.57–2.70 inches) and a weight of 56.0–59.4 g. The ball is pressurized to about 12–14 psi (0.8–1.0 bar) when new; some balls are “pressureless” and rely on a solid core that maintains weight but not bounce.

Most balls used in competition are two-piece spheres with a rubber core wrapped in felt, typically cut from wool-blend felt. The felt smooths airtime, influences aerodynamics and bounce, and must be durable for rallies.

There are different types: standard competition balls (ITF-approved) with star ratings (1-star, 2-star, or 3-star). Three-star balls are used in most professional matches; one-star balls are usually for practice or teaching. In training, players and clubs often use low-compression or non-pressurized balls, which have a softer feel and slower bounce suitable for beginners.

Storage and maintenance: Balls should be kept in a closed can to preserve pressure; once a can is opened, the bounce deteriorates over time and used balls are swapped out.