Size: ø 57.2 mm Sportime Pool Billiard Balls: For your pool table - The Sportime Pool Billiard Balls are made from durable plastic. The black numbers are engraved, ensuring they do not wear off even after years of intense use. The pool balls are precisely ground to within 1/10 mm, offering excellent and accurate rolling properties. 16 billiard balls in a box. Available in 2 sizes - The billiard balls come in 2 sizes: The ø 38 mm balls are suitable for tabletop games, while ø 57.2 mm is the standard tournament size for pool billiard balls. Product details: Material: Plastic, Available in: ø 38 mm or ø 57.2 mm, Ground to within 1/10 mm accuracy.