Type: Inflated rubber playground ball (commonly known as a "kickball"); Size: 8.5 to 10 inches (21.5 to 25.4 cm) in diameter; Material: Rubber or synthetic rubber; must be inflated and bouncy
Why people argue about this
People often assume that the ball size is a fixed measurement like in baseball when it's clearly stated as a range of 8.5 to 10 inches, leading to arguments about whether a ball slightly larger or smaller than 9 inches should be used. The confusion arises because kickball doesn't have a strict uniformity rule for ball sizes the way baseball does, allowing flexibility within those parameters.
