WP3 The Ball
WP 3.1 The ball shall be round and shall have an air chamber with a self-closing valve. It shall be waterproof, without external strapping or any covering of grease or similar substance.
WP 3.2 The weight of the ball shall be not less than 400 grammes and not more than 450 grammes.
WP 3.3 For games played by men, the circumference of the ball shall be not less than 0.68 metres and not more than 0.71 metres, and its pressure shall be 55 – 62 kPa (kilo Pascal’s) (8 – 9 pounds per square inch atmospheric).
WP 3.4 For games played by women, the circumference of the ball shall be not less than 0.65 metres and not more than 0.67 metres, and its pressure shall be 48 – 55 (kilo Pascal’s) (7 – 8 pounds per square inch atmospheric).