Official size and weight ball has 2 large bells inside that “Ring” when the ball is in motion. Super soft composite cover ball has a leather-like feel and a rubber bladder with the 2 bells inside. Perfect for indoor or outdoor volleyball. Official size volleyballs are approx. 8-1/4” in diameter, which is the same size as a size 4 soccer ball but significantly lighter, so you can also use this ball as a beginner soccer ball or in a variety of other activities. This audible volleyball is great for all players, including the blind and sight-impaired.